Exchange Server Upgrades and Migrations

Exchange Server Upgrades and Migrations

Exchange Server Upgrades and Migrations

Upgrades and migrations for Microsoft Exchange Server can seem like a complex and difficult process. However in most cases a migration is able to follow a standard process, with only those special or unique characteristics of the Exchange Server environment likely to cause problems or require additional planning and effort.

The first thing to be aware of when planning your Exchange Server migration is that in-place upgrades of Exchange Server are not possible

For example, you cannot upgrade an Exchange Server 2007 server to Exchange Server 2010, or an Exchange Server 2010 server to Exchange Server 2013.

The reasons for this are that the server architecture and internal workings of Microsoft Exchange Server often change so much between major releases that upgrades would become perilous exercises that are nearly impossible to adequately test for. Instead, an Exchange Server upgrade from one version to another involves a migration of services and data from old servers to new servers.

The upgrade scenarios for Exchange Server are typically N-2. In other words, a version of Exchange Server can be migrated to from the previous two versions, but not from any older versions

For example, Exchange Server 2013 can be migrated to from Exchange Server 2007 and 2010, but not from Exchange Server 2003. An Exchange Server 2003 organization would need to first migration to 2007 or 2010 before they could migration to Exchange Server 2013.

For more information on some of the supported migration scenarios refer to the following resources:

  • Migrating to Exchange Server 2016
  • Upgrading to Exchange Server 2013
  • Exchange Server 2010 Migration

Exchange Server Pro has published a number of migration guides for Exchange Server migration scenarios:

  • Exchange Server 2010 to 2013 Migration
  • Exchange Server 2003 to 2010 Migration
  • Exchange Server 2007 to 2010 Migration

I’ve also produced a Pluralsight training course for Exchange Server 2016 migration:

  • Migrating to Exchange Server 2016 on Pluralsight

For the purposes of this article an “upgrade” refers to the process of moving your organization’s Exchange Server environment to a newer version, for example from Exchange Server 2010 to Exchange Server 2013.

If you are looking for information about upgrading in the sense of service packs or cumulative updates, please refer to the following resources instead:

  • Installing Cumulative Updates for Exchange Server 2016
  • Installing Cumulative Updates and Service Packs for Exchange Server 2013
  • How to Install Updates on Exchange Server 2013 CAS Arrays
  • How to Install Updates on Exchange Server 2010 Database Availability Groups

Alternatives to Exchange Server Migrations

For organizations that do not wish to upgrade their on-premises Exchange Server environment there is also the option to migration to Exchange Online, which is the cloud hosted version of Exchange Server that forms a part of the Microsoft Office 365 service.

Office 365 migrations can be performed in multiple ways. For an overview of the Office 365 migration scenarios, read my article on methods for migrating to Office 365 or download the white paper Email Migration to Office 365, which gives a comprehensive overview of hidden challenges and how to overcome them.

How to migrate from Exchange 2010 to Office 365

How is the movement from Exchange 2010 to Office 365 any not quite the same as different situations?

Initially, before Exchange 2010, there was no real way to make a Hybrid situation with Office 365. Additionally, Exchange 2010 is a standout amongst the most famous source servers. That is on the grounds that for organizations which have later server forms, it would be a disgrace to leave to the cloud presently, moderately not long after subsequent to conveying another Exchange discharge, and when the help is as yet accessible. At last, there are some extra advances you have to take when you move from Exchange 2010 to Office 365.

This article exhibits a short Exchange 2010 to Office 365 movement control, to tell you the best way to design this adventure. Also, how to make it simpler.

Local Exchange 2010 to Office 365 relocation

Trade 2010 is the most seasoned Microsoft-made letter box server to be incorporated into the Microsoft Exchange Server Deployment Assistant. That is uplifting news. The Assistant is an instrument which asks you inquiries and produces an Exchange to Office 365 movement plan. It incorporates a large portion of the mainstream movement situations. Remember that this device is implied basically for single-woodland, single-area conditions. In the event that you have a progressively unpredictable organization, plan for some mystery.

There are three local ways you can take to get your organization from Exchange 2010 to Office 365:

Cutover movement, which is the most direct choice. You could state it cuts letter drops from the source server and glues them in the objective condition.

Half and half sending, which empowers Exchange 2010 and Office 365 to coincide.

PST import – or the manual methodology.

Trade 2010 to Office 365 Cutover Migration

The cutover relocation is as basic as getting all clients from the source server and gluing them in Office 365. Sounds basic, yet there is substantially more to that. In another article, you can locate an itemized cutover relocation plan. Beneath, you can discover a few stages you have to take before you relocate letter drops from Exchange 2010 to Office 365.

In the first place, you have to set up your condition. The arrangement and arranging may take less time than the real movement, however, regardless it requires a great deal of consideration. Underneath, you can locate a short undertaking rundown for a cutover relocation.

Update your Exchange 2010 server to SP3. While it isn’t required, it is exceedingly suggested.

Before you play out the cutover relocation, you should debilitate catalog synchronization and bound together informing, on the off chance that they are turned on.

Empower and arrange Outlook Anywhere. In the most up to date Exchange Server seasons, this is finished of course. In Exchange 2010; in any case, you have to finish this progression all alone. To effectively design Outlook Anywhere, you have to introduce a trusted SSL endorsement and the RPC over HTTP segment on your server. You can test whether the setup went well by interfacing with your Exchange 2010 from outside of your system. This will be tried naturally when you associate Office 365 to Exchange 2010, however the manual test will spare you some conceivable issue later.

Dole out authorizations. There are sure authorizations you should dole out to the record utilized for relocation.

It is basic practice to utilize a committed client represent the movement, which has just the insignificant required authorizations doled out. The consents the moving record needs are ApplicationImpersonation and View-Only Configuration for the Exchange Server and Office 365. Furthermore, the objective Office 365 condition requires View-Only Recipients job and User the board chairman on the off chance that it is likewise in charge of re-making clients in Exchange Online.

Make a mail-empowered security bunch in Office 365. Something else, the movement administration can’t arrangement any relocated gatherings as security bunches in Office 365

Check your space in Office 365. It expects you to include a TXT record in your DNS zone.

Use Exchange Admin Center to make a relocation endpoint. The endpoint contains all the data important to interface your Exchange 2010 server to Office 365.

Make and begin the cutover relocation group. The bunch incorporates all letter drops and requires the relocation endpoint designed a stage previously. This is the moment that the real movement occurs. After the information move is done, it merits confirming if everything had gone well. You likewise need to dole out licenses to clients.

Presently for the post-movement cleanup, switch your space’s MX record to point to Office 365.

After the TTL passes, messages are steered straightforwardly to Office 365. You can erase your movement cluster and decommission the on-premises servers.

The relocation is less frightening when you see what you need to do on a rundown. All things considered, recall that the entire errand requires a great deal of work and time. It might likewise incorporate a few stages which have not been recorded previously. It is ideal to ponder the theme a long time before endeavoring the relocation.

Trade 2010 and Office 365 Hybrid

The Hybrid sending is a sort of relocation and the sky is the limit from there. It is a cutting edge way to deal with the organized relocation accessible for Exchange 2003 and 2007. Trade 2010 and Office 365 Hybrid is a situation where the on-premises Exchange and Exchange Online coincide. This technique is particularly valuable if there is a great deal of information to move and the procedure will undoubtedly take a ton of time. Half breed is the main local strategy accessible for movement of more than 2000 letter drops. Indeed, Hybrid is suggested for movement of 150 post boxes and that’s only the tip of the iceberg.

There are associations which don’t utilize the Hybrid sending as a middle of the road arrange, however as the last condition, which has clients disseminated to both on-premises and the online situations, contingent upon what every client needs.

The Hybrid condition is made utilizing a committed Hybrid Configuration Wizard (HCW). See this article for a well-ordered guide on the best way to utilize the HCW and take care of issues associated with conveying a half breed condition.

Movement by PST

The last local movement utilizes the Office 365 PST Import Service. The general thought is to fare Exchange 2010 post boxes to PST documents, and after that to transfer them into Office 365 association. This strategy requires an administrator to do some manual work. This incorporates making Office 365 condition for all intents and purposes without any preparation.

Sending out all letter drops to PST is best finished with PowerShell and New-MailboxExportRequest. For full guidelines on the most proficient method to play out a mass letter drop fare to PST, counsel this article. The PST records should be in a common letter drop or on a document server. From this area, you need to transfer them to the Azure stockpiling area and make a CSV mapping record. The PST Import administration utilizes the mapping document to import PST records to the correct client letter boxes.

Microsoft additionally offers an alternative to deliver physical drives to them, which expects you to duplicate PST documents to physical stockpiles and to send them to Microsoft. The expense for this administration is $2 per GB of information.

Local constraints

Every one of the above local strategies for Exchange 2010 to Office 365 relocation has a few disadvantages. The Cutover relocation is a win big or bust arrangement and isn’t prescribed for more than 150 post boxes. It additionally does not permit Exchange and Office 365 conjunction. The Hybrid arrangement takes a great deal of time, and you are probably going to experience a few obstructions. With Office 365 Import Service, I don’t have the foggiest idea where to start. PST documents are… old. PST Migration is neither programmed, nor quick or dependable. It is just a decent choice on the off chance that you don’t have much information to move and you wouldn’t fret reproducing your Exchange 2010 condition in Office 365 starting with no outside help.

There are likewise local restrictions which are basic for every one of the arrangements recorded previously:

In numerous means of the relocation, you should utilize PowerShell. Despite the fact that it is truly significant to realize how to utilize this ground-breaking scripting language, you need a specific capability level. Learning on the fly during this unpredictable procedure may be distressing for you and hurtful to the (server) condition.

For the best movement experience, you have to overhaul your servers to the most up to date form. It is prescribed to get your Exchange 2010 to SP3. Along these lines, on the off chance that you have not refreshed your machines, get ready for some support.

Personal time is unavoidable, particularly on the off chance that you need to move open organizers. You need some cautious arranging, particularly if the assets on your servers are utilized nonstop.

Sifting isn’t accessible. Neither Cutover nor Hybrid Migration can give you a chance to channel things that are moved to Office 365.

The impediments of local arrangements power numerous organizations to utilize outsider apparatuses for movement.

Trade 2010 to Office 365 movement – the easy way

The easy method to move Exchange 2010 letter drops to Office 365 is to utilize an Office 365 relocation apparatus:

The movement instrument introduced in the video is CodeTwo Office 365 Migration. This product changes the movement procedure from the manager’s bad dream to a simple and programmed involvement and empowers a few highlights which are not accessible in the local situations.

Here are a portion of the key highlights of CodeTwo Office 365 Migration:

Programmed design – the product gives an agenda of the movement prerequisites and setup errands and does the greater part of the manager’s work. For instance, CodeTwo Office 365 Migration consequently makes clients in Office 365 and allots the required administration jobs to the client playing out the movement.

Planning – you can design your movement occupations, plan them to keep running in picked time periods and disregard them. The program can consequently send you relocation reports to tell you how the change goes and when it is finished.

Progressed sifting alternatives – you can relocate picked gatherings of clients and even select to move just a portion of their things, in light of a period and organizer channel. This lets you, for instance, relocate just the latest messages and date-books, change to Office 365 and afterward move the more established things to the cloud.

Office 365 to Office 365 Migration Guide – While Keeping the Same Domain Name

Introduction

This is the complete onboarding task stream for migrating mailboxes from one Office 365 tenant to another Office 365 tenant.

Complete each step in the request listed. Links to corresponding Knowledge Base articles are given.

This guide is just valid if the domain name is staying the same at the Destination. If the domain name is changing, allude to the Office 365 to Office 365 Migration Guide – While Changing the Domain Name.

The MSPComplete section includes the steps to convey the Device Management Agent (DMA) to users. This is an Agent which includes modules for HealthCheck for Office 365 and DeploymentPro. Deploying DMA to end users is a prerequisite if you will be using HealthCheck for Office 365 and/or DeploymentPro. The steps for HealthCheck for Office 365 have been omitted from this guide because your end users are already using Office 365.

DeploymentPro can be utilized to configure the Outlook mail profiles after the migration.

Note: DeploymentPro is included with the User Migration Bundle license. DeploymentPro cannot be purchased as a standalone service license, and it cannot be added to the single-use mailbox migration license. If you wish to remotely configure Outlook mail profiles using DeploymentPro after a migration, purchase the User Migration Bundle license.

MigrationWiz now supports the capability to share migration projects across a Workgroup. Migration projects are never again tied to individual accounts, they are tied to Workgroups. At the point when Workgroup Administrators turn on the Project Sharing feature, all Agents besides those who are Inactive are able to see all migrations projects. For more information, visit Project Sharing in MigrationWiz.

Office 365 to Office 365 migrations that are keeping the same domain name differ from the standard approach followed in other migration guides, because Microsoft just allows a domain to reside in one tenant at a time. For this reason, the following extra steps are included in this guide:

Adding a recipient mapping, under Advanced Options, to guarantee that all email retains the ability to be answered to, post-migration.

Removing the domain from the Source tenant.

Verifying the domain on the Destination tenant.

The users should first be added to MSPComplete using the vanity domain name. A MSPComplete subscription can then be added to each user. Be that as it may, before beginning the migration, the user addresses should be changed to utilize the .onmicrosoft.com domain names at both the Source and Destination, rather than the vanity domain names.

Notes:

There will be some email downtime with this migration because of the time required to remove the domain on the Source tenant and add it on the Destination tenant. This is because Microsoft just allows the same domain to exist on one Office 365 tenant at a time. Exchange Online Protection (EOP) can’t route email for the domain during the timeframe when the domain is removed from the Source tenant and added to the Destination tenant, assuming the MX record is pointed at EOP. This results in senders getting a non-conveyance report (NDR). Read the Move domains and settings from one EOP organization to another EOP organization TechNet article for options to line email during this time.

Utilization of RecipientMapping is always recommended but is mandatory if you delete the domain before you start your Delta migration pass.

Prepare the Source Environment

Create an administrator account in Office 365 to be utilized for migration, or utilize the global admin account for the tenant. Read the How would I create an administrator account in Office 365, and then utilize this during migration? article for more information.

Test mailbox access.

Note: Test access to the tenantname.onmicrosoft.com addresses, not to the domainname.com addresses. Make beyond any doubt that the tenantname.onmicrosoft.com account is attached to each mailbox in Office 365. As a matter of course, it should be attached, but if not, it will need to be added as an alias to each account. This can be done through the Office 365 admin portal or via PowerShell scripts. Read the How would I test mailbox access? article for more information.

Prepare the Destination Environment

Create an administrator account in Office 365 to be utilized for migration, or utilize the global admin account for the tenant. Read the How would I create an administrator account in Office 365, and then utilize this during migration? article for more information.

Set up accounts on Office 365 and assign licenses. These can be created in several ways:

Manually, one at a time. Read the Add users individually or in mass to Office 365 article from Microsoft for more information.

By mass import, via CSV file. Read the Add several users at the same time to Office 365 article from Microsoft for more information.

By PowerShell script. Read the Create user accounts with Office 365 PowerShell TechNet article for more information.

By DirSync, AAD Sync or AAD connect. Read the How would I synchronize my Azure Active Directory objects to Office 365? article for more information.

Using the BitTitan Sync Tool. Read the BitTitan Sync Program article for more information.

Test mailbox access.

Note: Test access to the tenantname.onmicrosoft.com addresses, not to the domainname.com addresses. Make beyond any doubt that the tenantname.onmicrosoft.com account is attached to each mailbox in Office 365. Naturally, it should be attached, but if not, it will need to be added as an alias to each account. This can be done through the Office 365 admin portal or via PowerShell scripts. Read the How would I test mailbox access? article for more information.

Prepare the tenant to send and receive large mail items. Read the How would I migrate large mail items to Office 365? article for more information.

MSPComplete Steps

Create the customer. Read the View, Add, and Edit Your Customers article for more information.

Create the Source and Destination endpoints. Read the View, Add, and Edit Customer Endpoints

article for more information.

For the Source endpoint:

Click Endpoints > Add Endpoint > Enter endpoint name > For endpoint type, select Office 365.

Click the Provide Credentials radio button, and enter the admin account credentials.

Notes:

This should be a global admin account. If creating a separate admin account for the motivation behind migration, allude to the Office 365 section in the How would I create an administrator account for login? article.

You should utilize the tenantname.onmicrosoft.com address, for the admin account domain name.

For the Destination endpoint:

Click Endpoints > Add Endpoint > Enter endpoint name > For endpoint type, select Office 365.

Click the Provide Credentials radio button, and enter the admin account credentials.

Notes:

This should be a global admin account. If you are creating a separate admin account for the motivation behind migration, allude to the Office 365 section in the How would I create an administrator account for login? article.

You should utilize the tenantname.onmicrosoft.com address for the admin account domain name.

Add users to your MSPComplete customer. From your MSPComplete customer dashboard, click Users > Add Users > Add Users Through an Endpoint (Recommended).

Apply a User Migration Bundle license to each user. From the Users tab, select all the users that you wish to subscribe, click the Apply User Migration Bundle License button, and confirm. Read the Apply User Migration Bundle licenses to the Customer’s Users article for more information.

Send DMA to users. Once DMA has been sent to users, check the Users tab in MSPComplete. This will be populated with the user accounts that have DMA installed. DMA can be sent by either of these options:

Via Group Policy Object (GPO).

Note: This is the recommended methodology because no closure user interaction is required. Read the How would I send the Device Management Agent with a Group Policy Object? article for more information.

Via email. Read the How would I send the Device Management Agent through email? article for more information.

DeploymentPro Steps

Launch DeploymentPro.

Go to All Products > Device Management, then click on DeploymentPro on the far left and pursue the prompts to launch.

Select a customer from the list by clicking on the customer name.

Note: The status column will show Enabled when a customer account has had DMA conveyed to users.

Configure customer DeploymentPro module:

Enter the Domain.

Select the Destination endpoint.

Checkmark the Auto-populate box.

In the Client Interface Configurations section, upload your company logo and add supporting text.

Note: We strongly recommend doing this, because this is the logo and text that end users will find in a desktop spring up when they are prompted to reconfigure their Outlook profiles. If you don’t upload your own logo, the default BitTitan logo will be included instead.

Save and continue.

Activate DeploymentPro module for users.

Either select all users (by putting a checkmark in the case to the left of the Primary Email column heading) or select the individual users (by putting a checkmark in the boxes to the left of the user email addresses).

Note: DeploymentPro is included with the User Migration Bundle license. DeploymentPro cannot be purchased as a standalone service license, and it cannot be added to the single-use mailbox migration license. If you wish to remotely configure Outlook mail profiles using DeploymentPro after a migration, purchase the User Migration Bundle license.

Click the Schedule Cutover button.

Schedule profile cutover date.

Set the date and time for the Outlook profile configuration to occur, and click the Schedule Cutover button.

Notes:

The DeploymentPro module will install on user devices immediately and then run silently until this date.

The profile cutover date should be set to a date and time that is shortly after MX record cutover.

On the profile cutover date, users will be guided through the reconfiguration of their Outlook profile.

How to migrate mailboxes from one Office 365 tenant to another

This article explains how to migrate mailboxes and service settings from one Office 365 tenant to another Office 365 tenant in a business-merger scenario

How to migrate mailboxes from one Office 365 tenant to another

If you have in excess of 500 users to migrate or a large amount of SharePoint data to migrate, it’s a smart thought to work with an Office 365 partner.

The scenario in this article is based on two fictional companies – Contoso.com and Fabrikam.com – using two separate Office 365 tenants. Contoso has purchased Fabrikam and is moving the Fabrikam users and data to the contoso.com Office 365 tenant.

Scenario: Migrate using a third party migration tool

This scenario assumes that user, gathering and other objects from the Fabrikam Company will be manually created in Office 365, imported into the portal via script, or converged into the Contoso Active Directory through Active Directory Domain Services (AD DS) consolidation.

Whenever complete, all Fabrikam accounts will exist in the Contoso.com Office 365 tenant, and will all utilization @fabrikam.com for the UPN. The final addressing scheme was chosen for simplicity and brevity but can of course be modified to meet your requirements.

Planning: Two weeks before you migrate

If using a third party migration tool to migrate your users, purchase the needed licenses for your migration.

Client considerations

For Outlook 2010 or above, you just need to remove the Outlook user profile and create it again.

For Outlook 2007 and Outlook 2010, when you are restarting the client, auto-discover will configure the client and modify the .OST file.

For the skype for business client, once migration is complete, since the process creates a new profile, you will need to add contacts.

Tenant preparation and licensing

The source tenant is the Fabrikam Office 365 tenant from which you are migrating users and data. The target tenant is the Contoso Office 365 tenant to which you are migrating.

Increase licenses in Target Office 365 tenant to accommodate all mailboxes that will be migrated from the source tenant.

Create Administrator accounts in source and target tenants for use in migrating from Office 365 to another Office 365. Some migration tools may require more than one admin account in the source tenant to optimize the data throughput.

Room, resource, distribution gathering, and user object creation in the target tenant

To create the resources in the target (Contoso) tenant:

If the Azure AD Connect tool will be utilized to sync all objects from the Contoso Active Directory Domain Services (AD DS), the objects from the source (Fabrikam) tenant AD DS must be created in the target tenant (Contoso) AD DS through consolidation.

AD DS consolidation can be done using various AD DS tools. Consolidation can take extra time and planning depending on what number of objects are being moved, so it can be completed ahead of the migration project.

Verify that all new users and groups are synced to the Contoso.com target tenant via directory synchronization. The objects should appear as user@contoso.onmicrosoft.com in the new tenant since the Fabrikam domain has not been moved over at this time. The primary email address for the users and groups can be updated to @fabrikam.com after the domain move is complete.

If directory synchronization will not be utilized, or if any Rooms, Resources, Groups or Users are managed in the Microsoft 365 admin center of the source tenant; these objects must be created in the target tenant. Objects can be created manually in the Microsoft 365 admin center or for larger numbers import a CSV file by using the mass add feature in the Microsoft 365 admin center, or by using Windows PowerShell.

End-user communications

To communicate the migration to the end users in your organization:

Create a communication plan and begin to notify users of the upcoming migration and service changes.

After migration, the Auto-Complete List (also known as the nickname cache) will have to be cleared on all Outlook clients. To remove all recipients from your Auto-Complete list in Outlook 2010 later, see Manage suggested recipients in the To, Cc, and Bcc boxes with Auto-Complete.

Make users aware of how to connect to Outlook Web App with their new sign on information in case they have an issue after migration.

Preparation and pre-migration activities: Three days before you migrate

Domain preparation

To prepare the domain for migration, complete the following steps.

Begin domain verification process on target (Contoso) tenant for the Fabrikam.com email domain.

In the contoso.com Microsoft 365 admin center, add the Fabrikam.com domain and create TXT records in Domain Name Systems (DNS) for verification.

The verification will fail because the domain is still in use in the other tenant.

Performing this step presently will allow the DNS record time to propagate as it can take as long as 72 hours. Final validation will occur later in the process.

Migration scheduling

To schedule the migration:

Create master list of user mailboxes you want to migrate.

Create mailbox mapping .CSV file for the third-party migration tool you are using. This mapping file will be utilized by the migration tool to match the source mailbox with the target tenant mailbox when migration occurs. We recommend that you utilize the *.onmicrosoft.com ‘initial’ domain for mapping the source accounts since the custom email domain will be constantly changing.

Mail exchanger record (MX record) time to live (TTL) test

Next, you’ll schedule the TTL test.

In DNS, change the TTL value on the MX record for the primary email domain you wish to transfer to a small number (for example 5 minutes). If the TTL cannot be brought down to 5 minutes, make note of the lowest value. Example, if the lowest value is 4 hours, the MX record will have to be changed 4 hours before your migration begins.

Mx Lookup can be utilized to verify MX and DNS changes.

Disable directory sync in source tenant

In the source tenant Microsoft 365 admin center, disable directory sync. This process can take 24 hours or all the more so it must be done ahead of the migration. Once disabled in the portal, any changes to the source tenant AD DS will never again sync to the Office 365 tenant. Adjust your existing user and gathering provisioning process accordingly.

Migration: The day you migrate

These are the steps you’ll need the day you perform the migration.

MX record change – Stop inbound mail stream

Change your primary MX record from Office 365 to domain that is not reachable, for example “unreachable.example.com”. Internet mail servers attempting to convey new mail will line the mail and attempt redelivery for 24 hours. Using this method, some email may return a non-conveyance report (NDR) depending on the server attempting to convey the email. If this is an issue utilize a MX record backup service. There are many third party services that will line your email for days or weeks. Once your migration is complete, these services will convey the lined mail to your new Office 365 tenant.

Tip

If your TTL is short, for example, five minutes, this step can be done at the end of the work day to cause less disruption. If you have a larger TTL, you must change the MX record ahead of time to allow the TTL to lapse. Example, a four hour TTL must be changed before 2 PM if you plan to begin migrations at 6 PM.

Verify your MX and DNS changes if necessary. Nslookup or a service like MxToolbox can be utilized to verify MX and DNS changes.

Source tenant preparation

The primary email domain, fabrikam.com, must be removed from all objects in the source tenant before the domain can be moved to the target tenant.

If you had also set up your domain with a SharePoint Online public website, then before you can remove the domain, you first have to set the website’s URL back to the initial domain.

Remove all Lync licenses from the users in the source tenant using Lync admin portal. This will remove the Lync Sip address connected to Fabrikam.com.

Reset default email addresses on Office 365 source mailboxes to the initial domain (fabrikam.onmicrosoft.com).

Reset default email addresses on all Distribution Lists, Rooms and Resources to the initial domain (fabrikam.onmicrosoft.com) in source tenant.

Remove all secondary email (proxy addresses) from user objects that are still using @fabrikam.com.

Set default domain in source tenant to fabrikam.onmicrosoft.com routing domain (in the admin portal, click your company name in the upper right corner).

Use Windows PowerShell command Get-MsolUser – DomainName Fabrikam.com to retrieve a list of all objects that are still using the domain and blocking removal.

For common domain removal issues, see You get a blunder message when you try to remove a domain from Office 365.

Target tenant preparation

Complete the verification of the Fabrikam.com domain in the contoso.com tenant. You may have to wait one hour after removing the domain from the old tenant.

Configure auto-discover CNAME (internal/External) optional.

If you are using AD FS, configure the new domain in target tenant for AD FS.

Begin mailbox activation in the contoso.com tenant > Assign licenses to all of the new user accounts.

Set the Fabrikam.com email domain as the primary address on the new users. This can be done by selecting/editing multiple unlicensed users in the portal or by using Windows PowerShell.

If you are not using the password hash sync feature, pass-through authentication or AD FS, set password on all mailboxes in the target (Contoso) tenant. If you are not using a common password, notify users of the new password.

Once mailboxes are licensed and active, transition the mail routing. Point the Fabrikam MX record to Office 365 target (Contoso) tenant. At the point when the MX TTL expires, mail will begin to stream into the new empty mailboxes. If you are using a MX backup service, you can release the email to the new mailboxes.

Ways to migrate multiple email accounts to Office 365

Your association can relocate email to Office 365 from different frameworks

Your directors can Migrate post boxes from Exchange Server or Migrate email from another IMAP-empowered email framework. What’s more, your clients can Have clients import their own email their own email, contacts, and other post box data to an Office 365 letter box made for them. Your association likewise can Work with an accomplice to relocate email.

Before you begin an email movement, survey points of confinement and best practices for Exchange Online to ensure you get the exhibition and conduct you expect after relocation.

See Decide on a relocation way or Exchange movement counselors for assistance with picking the best choice for your association

Another choice accessible to help you with your email relocation is FastTrack Center Benefit for Office 365. FastTrack authorities can enable you to design and play out your movement. For more data, see Data Migration.

Relocate letter drops from Exchange Server

For relocations from a current on-premises Exchange Server condition, a head can move all email, timetable, and contacts from client letter drops to Office 365.

There are three kinds of email relocations that can be produced using an Exchange Server:

Relocate all post boxes without a moment’s delay (cutover movement) or Express movement

Utilize this kind of movement in case you’re running Exchange 2003, Exchange 2007, Exchange 2010, or Exchange 2013, and if there are less than 2000 post boxes. You can play out a cutover relocation by beginning from the Exchange administrator focus (EAC); see Perform a cutover movement to Office 365. See Use express movement to move Exchange letter boxes to Office 365 to utilize the Express relocation.

Significant

With cutover relocation, you can climb to 2000 post boxes, however because of period of time it takes to make and move 2000 clients, it is increasingly sensible to move 150 clients or less.

Move post boxes in clumps (organized relocation)

Utilize this sort of movement in case you’re running Exchange 2003 or Exchange 2007, and there are more than 2,000 letter drops. For an outline of organized movement, see What you have to think about an arranged email relocation to Office 365. To play out the relocation errands, see Perform an arranged movement of Exchange Server 2003 and Exchange 2007 to Office 365.

Relocate utilizing a coordinated Exchange Server and Office 365 condition (crossover)

Utilize this kind of relocation to keep up both on-premises and online letter drops for your association and to step by step move clients and email to Office 365.

Utilize this sort of relocation if:

You have Exchange 2010 and more than 150-2,000 letter drops.

You have Exchange 2010 and need to move letter drops in little clumps after some time.

You have Exchange 2013.

For more data, see Plan an Exchange Online half and half sending in Office 365.

Use Office 365 Import Service to move PST-records

On the off chance that your association has numerous huge PST records, you can utilize the Office 365 Import Service to relocate email information to Office 365.

You can utilize the Office 365 Import Service to either transfer the PST records through a system or to mail the PST documents in a drive that you get ready.

For guidelines, see Office 365 Import Service

Relocate email from another IMAP-empowered email framework

You can utilize the Internet Message Access Protocol (IMAP) to relocate client email from Gmail, Exchange, Outlook.com, and other email frameworks that help IMAP movement. When you relocate the client’s email by utilizing IMAP movement, just the things in the clients’ inbox or other mail envelopes are moved. Contacts, logbook things, and undertakings can’t be relocated with IMAP, however they can be by a client.

IMAP relocation likewise doesn’t make letter drops in Office 365. You’ll need to make a letter drop for every client before you move their email.

To move email from another mail framework, see Migrate your IMAP letter drops to Office 365. After the email relocation is done, any new mail sent to the source email isn’t moved.

Have clients import their own email

Clients can import their own email, contacts, and other post box data to Office 365. See Migrate email and contacts to Office 365 to figure out how.