CodeTwo Office 365 Migration


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free support
during migration

Frequently Asked Questions - CodeTwo Office 365 Migration

Take a look at the list of frequently asked questions about CodeTwo Office 365 Migration:

  1. Why do I need this program?

    Using CodeTwo Office 365 Migration you will significantly reduce the time required to successfully move mailboxes from on-premises Exchange servers (including hosted Exchange services) or email from IMAP servers to Office 365 (Microsoft 365). The program also lets you migrate data between two Office 365 tenants. The main benefits of this migration tool include:

    • Easy-to-use graphical interface that minimizes the need for PowerShell scripts.
    • Direct mailbox migrations from Exchange 2010/2013 and later to Office 365, which eliminates the need for upgrades, hybrid deployments, etc.
    • Migrations between Office 365 tenants.
    • Enhanced IMAP migrations to Office 365. Learn more...
    • Convenient reporting features that facilitate troubleshooting.

    See a full comparison of CodeTwo Office 365 Migration and Office 365 native migration tools.

  2. Is there a free trial? What are the limitations?

    Yes, there is. You can download the free trial version here.

    The trial works for 30 days and allows you to migrate up to 10 items per folder (after you switch to the full version, CodeTwo Office 365 Migration will migrate the remaining items). Other than that, it has all the features of the full version of the program.

  3. How does the CodeTwo Office 365 Migration solution work?

    Migrations from Exchange Server are achieved by connecting to a source server and a target Office 365 (Microsoft 365) tenant via Exchange Web Services (EWS). Connecting to a source legacy Exchange server (e.g. Exchange 2010 without SP1) is also possible via a dedicated MAPI profile. This way, CodeTwo Office 365 Migration can read the contents of mailboxes on your source server and copy them to mailboxes in Exchange Online. The complete migration process is shown in the video below:

    Connection to Office 365 is done via the OAuth 2.0 authorization protocol to provide maximum security. During the connection setup, the program is registered in the Microsoft Entra ID (Azure Active Directory) of each tenant that is used in the migration process. The registration process is completely automated by the program, but you can perform the registration manually as well. Learn more…

    To perform migrations via IMAP, the application connects to source server accounts similarly to an email client (source account credentials are required) and copies emails to target server mailboxes. Learn more about IMAP migrations...

    All you have to do to perform the migration is create target mailboxes (or configure CodeTwo Office 365 Migration to create and activate mailboxes for you).

    Learn more about how the program operates

  4. Can I migrate mailboxes between two different Office 365/Microsoft 365 tenants?

    Yes, you can. CodeTwo Office 365 Migration enables an easy migration from one Office 365 (Microsoft 365) tenant to another, which can come in handy e.g. in the case of company mergers or acquisitions. Learn more...

  5. Are migrations from IMAP servers supported?

    Yes, using CodeTwo Office 365 Migration you can replicate email from servers such as Google Workspace (G Suite), Zarafa, Zimbra, HCL Notes (formerly IBM Notes and Lotus Notes), Kerio Connect, etc., to Exchange Online. The application lets you customize and manage more aspects of IMAP migrations than by using Microsoft's native tools. Learn more...

    There are several limitations related to using the IMAP protocol. The migrations are limited to email folders only and you need to provide credentials to all user accounts that will be migrated. To learn more about IMAP migrations, go to this user's manual page.

  6. Are migrations from hosted Exchange supported?

    Yes, they are. The program connects to hosted Exchange via Exchange Web Services, which means you can migrate from those Exchange servers that support EWS (i.e. Exchange 2010 and newer).

    To perform the migration:

    • The admin account used to connect to the source server needs to be able to impersonate all mailboxes you want to migrate.
    • When configuring a migration job in the program, you need to import a CSV file with a list of paired source and target mailboxes. The file needs to include at least email addresses and IDs (GUIDs) of source and target mailboxes.

    For more details on how to migrate mailboxes from a hosted Exchange server to Microsoft 365 & Office 365 with CodeTwo Office 365 Migration, see the user’s manual.

  7. Can the program migrate encrypted emails?

    Yes, CodeTwo Office 365 Migration migrates emails encrypted by OME (Office 365 Message Encryption), signed with S/MIME or protected with a sensitivity label. However, keep in mind that such emails will keep their properties after the migration, which means they will remain encrypted and users from the target Microsoft 365 tenant will not be able to open and read them (as they are not the intended/original recipients).

    This is the expected behavior. Our program does not decrypt such messages during the migration.

  8. Can the program migrate archive mailboxes (In-Place Archives)?

    Yes, CodeTwo Office 365 Migration can be used to migrate archive mailboxes from Exchange Online and on-premises to selected mailboxes (either primary or archive) in your Microsoft 365 tenant.

    When configuring a migration job, go to the Mailbox type step and select the type of mailbox you want to migrate: primary, archive or both. Learn more in the user’s manual…

    If you intend to migrate Exchange Online archive mailboxes that are larger than 100 GB, consult this Knowledge Base article first.

  9. Does CodeTwo Office 365 Migration support organizations synced using Microsoft Entra Connect (Azure AD Connect) or other directory sync tools?

    Yes, the software supports migration from and to a hybrid environment. Learn more...

  10. Can the program migrate all languages?

    Yes. Content language does not affect the migration process. CodeTwo Office 365 Migration can move any item that contains special characters, regardless of the language set on the source and target server. Learn more in the user’s manual...

  11. What type of support do you offer for the product?

    Technical support for CodeTwo Office 365 Migration is free of charge and covers all types of issues. You can contact our technicians via email or phone, 24 hours a day, from Monday through Friday (find out more about CodeTwo support). Complex issues are resolved via remote sessions.

    All technical documentation for CodeTwo Office 365 Migration is available online:

  12. What is CodeTwo Office 365 Migration's licensing policy?

    The product is licensed through use. Each mailbox you start migrating automatically uses up 1 seat from your license pool. A single license lets you migrate both the primary mailbox and the archive mailbox provided that you enabled archiving (In-Place Archiving) for your source Exchange mailboxes. In addition, the program consumes 100 licenses to migrate Exchange public folders (regardless of their size).

    In other words, if you had a 200-mailbox license and started migrating 60 mailboxes, your license would still allow you to migrate, for example:

    • 140 mailboxes (primary and/or archive); or
    • 40 mailboxes (primary and/or archive) and public folders

    to Office 365 (Microsoft 365).

    What is more, the licensing model lets you install the software in any number of source environments. If you use the same license key, each migrated mailbox subtracts from the same, common license pool. This means that a single mailbox will not consume more than one license.

    More CodeTwo Office 365 Migration licensing details (user's manual)

  13. What if I already have a license and need extra seats?

    You can purchase extra seats by going to the online order formselecting Additional licenses and proceeding to complete the order.

    NOTE: In the 2nd step of the online order form, you will be asked to provide the license key that you wish to expand.

    If you received your CodeTwo Office 365 Migration license free of charge and now want to add seats to it, please contact our sales team for assistance.

  14. What type of data can be migrated?

    To learn more on what type of data is supported for migration, see this user's manual article.

  15. Do I have to install the program on a server?

    No, you don't. You can install CodeTwo Office 365 Migration on any machine (server or client) connected to the source organization if you plan to migrate from on-premises Exchange server.

    For tenant-to-tenant migrations or when migrating from hosted Exchange or IMAP servers, you can install the program on any machine (including a cloud-hosted virtual machine, like Microsoft Azure Virtual Machine), as long as that machine has Internet access and can connect to Office 365 (Microsoft 365).

    CodeTwo Office 365 Migration installation details (user's manual)

  16. What is the migration speed? Does CodeTwo Office 365 Migration impose any size or speed limits?

    No, our software does not introduce any new limits when migrating data to Exchange Online. The migration speed via EWS, as observed by Microsoft, is between 0.2 and 0.5 GB per hour

    Keep in mind that Office 365 (Microsoft 365) comes with a number of built-in limitations for EWS migrations. The main ones are:

    • 25 MB per-item limit – this means that items larger than 25 MB will be skipped during a migration. However, you can change this limit up to 150 MB – learn more in this Knowledge Base article.
    • Resource health-based throttling – present in cases of service availability issues.

    Other factors that may affect the migration performance are:

    • Source and target server throttling policies and limitations.
    • Data type and density (e.g. a mailbox with a smaller number of large items will migrate faster than one with a larger number of small items).
    • Migration server hardware.
    • Network infrastructure.

    For more, consult this Microsoft article.

    CodeTwo Office 365 Migration does not increase or decrease the standard speed of an EWS migration. However, it is possible to achieve higher migration speeds by:

    See this user’s manual article to learn more about how to speed up the migration process.

  17. How do I prepare for the migration?

    For details on migration requirements and pre-migration steps go to this user's manual page and choose your migration scenario.

  18. Does CodeTwo Office 365 Migration support multi-factor authentication?

    Yes, CodeTwo Office 365 Migration supports multi-factor authentication enabled on Office 365 (Microsoft 365) accounts.

  19. Does CodeTwo Office 365 Migration automatically create target users and mailboxes?

    Yes, it does. The process is performed based on source server’s user data and can be fully customized. The program also automatically assigns Office 365 (Microsoft 365) licenses to newly created target mailboxes. Learn more...

    Note that the program can only create primary mailboxes in your target Microsoft 365 tenant. If you are migrating archive mailboxes and you need to create (enable) them on your target server, you need to do that manually, as described in this Knowledge Base article.

  20. Can I define criteria based on which source and target mailboxes will be auto-matched?

    Yes, you can. Apart from using predefined matching patterns, you can also create your own. Learn more...

  21. Does CodeTwo Office 365 Migration migrate public folders?

    Yes, it does. Public folders are supported when migrating from on-premises Exchange servers or Office 365 (Microsoft 365).

    NOTE: To migrate public folders, you first need to create them in Office 365. Additionally, the admin account used in the program to configure the target Office 365 connection needs to be assigned the Owner permission level to the root public folder on that tenant and to all subfolders to which you plan to migrate your data. However, since public folders cannot exist in Office 365 and in on-premises Exchange server simultaneously, migrating them within hybrid environments requires some additional setup. Learn more in Knowledge Base

    Bear in mind that migrating public folders reduces your CodeTwo Office 365 Migration license by 100 users (regardless of the amount of data or the number of public folder mailboxes you are migrating).

  22. Is the free/busy info migrated as well?

    Free/busy statuses are generated on the fly by the Exchange Availability Service based on users' calendar information. This means that after CodeTwo Office 365 Migration copies your users' calendars to Exchange Online, the Office 365 (Microsoft 365) engine will take care of the rest and set the appropriate status.

  23. Does the program perform 2-way sync between source and target servers?

    No. CodeTwo Office 365 Migration creates exact 1:1 copies of source Exchange mailboxes, together with their folder structure, in the target Office 365 (Microsoft 365) tenant. The data is copied from the source environment to the target one, so no two-way sync takes place.

    However, the delta migration feature in the program lets you perform continuous one-way delta sync from source to target. With each delta migration run, new items that appeared on the source server are migrated to the target one (the already migrated items are skipped). Learn more about delta migration

    See also the next FAQ.

  24. Does CodeTwo Office 365 Migration affect data on the source server?

    No, it doesn't. The application only reads source server data and copies it to your Office 365 (Microsoft 365) organization – nothing is deleted from or modified on your source server.

  25. I want my users to still use source mailboxes after they have been migrated - can they do that?

    Yes, they can. The contents of the source mailboxes are not affected in any way, so your users can use these mailboxes indefinitely without any limitations.

    What is more, once you decide to retire your source server and move to the target one, use the delta migration feature in CodeTwo Office 365 Migration. This will restart your migration job, but the program will copy only those items that have been created on the source server after the initial migration.

  26. Is GoDaddy supported?

    Yes, you can use the program to migrate from/to Microsoft 365 from GoDaddy (also known as Office 365 from GoDaddy). The only requirement is that you need to have global admin privileges to your Microsoft 365 tenant at GoDaddy. For step-by-step instructions on how to perform the migration, read this blog article.

    GoDaddy’s hosted Exchange and IMAP email services are also supported as a source environment in your migration tasks.

  27. What do I do if I get an error...?

    Consult this Knowledge Base article for troubleshooting steps.

    If none of the suggestions from the article help, contact our Technical Support team.

    For general technical information about CodeTwo Office 365 Migration, refer to the user's manual.

    Answers to common queries can be found in the Knowledge Base.

  28. How to upgrade to version 3.0?

    To upgrade CodeTwo Office 365 Migration to version 3.0, you need to follow the steps specified in this article.