Mailbox migrations vary by source and destination but have a few things in common. The most commonly asked general questions are below. For specific steps and guidance based on your migration scenario, see our migration guides. 

By design, the migration caches the Mailbox and Project settings once it starts and is assigned to a migration server

MigrationWiz does not have any limitations on the mailbox size to migrate. We have migrated mailboxes that contain hundreds of gigabytes (GB) of data.

​​​Email that already exists in a Destination mailbox is not changed or affected in any way during the migration process.  MigrationWiz does not delete, change, or move any items that exist in the Destination mailbox before running a migration.  

Supported Mailbox Types

Encrypted Email

For all Source email systems, any email sent or received using third-party encryption plugins does not migrate using MigrationWiz. This email needs to be decrypted before it can be migrated.

Flagged Email

The Follow-Up condition rule item will be displayed in the Inbox or For Follow-Up Search folder as default in the O365 Outlook as well as Exchange.

The rule will not be triggered with Flag-Follow Up with a specific folder neither in Outlook or Exchange.

Migration between different domain suffixes

You may migrate data between email accounts that have different domain suffixes.

Automatic Replies (Out-of-Office Messages)

You can now migrate Out-of-Office messages from source mailboxes to destination mailboxes using different endpoints.

MigrationWiz supports this feature in the following source and destination endpoints:

• Microsoft Exchange Server.
• Microsoft 365.
• Google/G-Suit.

Permissions

With MigrationWiz you can automatically migrate mailbox folder permissions, allowing you to migrate folder, and calendar permissions for user and shared mailboxes. Avoiding manual re-application of permissions.

Folder Permissions

Folder permissions are migrated using the following approach:

• First, MigrationWiz tries to match the source primary SMTP email address to the destination primary SMTP email address.
• Next, MigrationWiz tries to match the source display name to the destination display name.

Mailbox Rules

With MigrationWiz you can migrate Mailbox Rules including Client-Side Rules from Outlook for specified conditions and actions. This works at the tenant level as well as regular (personal) mailbox settings.

Signatures

You can migrate the primary signature from source mailboxes to destination mailboxes using Google / G-Suite only within MigrationWiz.

In Google/G Suite migrations (at source or destination), MigrationWiz will migrate the signature as Default Signature at the destination mail.

Pre-existing Items

Email that already exists in a Destination mailbox is not changed or affected in any way during the migration process.  MigrationWiz does not delete, change, or move any items that exist in the Destination mailbox before running a migration.  

S/MIME Email

MigrationWiz can migrate S/MIME digitally signed messages with or without encryption.

Create a Mailbox Migration Project

1. From the MigrationWiz dashboard, click Go To My Projects.

2. Click Create Project.

3. Select a Mailbox migration type. 

4. Click Next Step.

5. Enter a project name and select a Customer from the list. In case the customer has not been created, follow the steps below:

   1. Click New.

   2. Provide the required details including the primary email domain and company name.

   3. Click Save.

6. Click Next Step.

O365 Mailbox Migrations

In O365 to O365 mailbox migration, MigrationWiz automatically adds the new ApplyLicensesToTargetMailboxesImport=1 support option. Please keep in mind that this support option does not pass the validation feature. When this happens, please use the However, if you are confident in your inputs/commands, you may proceed and save the options option at the bottom of the support options page to bypass this and save the support options.

Migrated Items

Certain mailbox items are always migrated, regardless of source or destination. 

Special cases in email migrations

Hidden Folders

If a system folder exists on both the source and the destination, MigrationWiz detects it and migrates items to that location.

For example, Exchange stores attachments in a hidden system folder called 'Files'. If the destination also has this folded, MigrationWiz automatically migrates the items. As these are hidden, it may appear they did not migrate.

If the content needs to migrate to a different folder, use folder mapping to specify the new destination folder. 

Encrypted Content

We migrate MIME content in an as-is state. S/MIME messages can be migrated and remain encrypted at the destination. Viewing them on the destination requires the same certificate used to encrypt them, including their corresponding private key. 

Messages with Azure Information Protection are migrated, but not viewable at the destination, as the source tenant policies are not available on the destination.
You can migrate them in a viewable format, by decrypting these messages on the source and migrating the decrypted emails.

If you need to encrypt them at the destination (this is optional), simply recreate the security policies on the destination and then reapply the policies to the migrated messages.

Our data retention and security policies can be reviewed on our BitTitan Data Security and Privacy Policy page.

Color Categories

The default colors are maintained during migration. However, if additional color categories have been defined at the Source, other than those supported at the destination, they are not migrated. Instead, they are converted to the default calendar color at the destination.

For example, Google supports more calendar colors than Microsoft 365. Any calendar colors on Google that are not any of the six (6) default colors on Microsoft 365 (blue, orange, green, purple, red, yellow) will be converted to the default color on Microsoft 365 (light red).

Calendar Meeting Links

Lync, Skype, or Teams events are migrated but do not usually work in the destination because the links are for the source environment. These events need to be recreated at the destination. There are exceptions to this rule, but they are not consistent.

Mailbox Migration FAQ

Licensing Large Items

However, you can restart the migration from where it left off by purchasing another mailbox license and resubmitting it for a new migration.​

Assign M365 Licenses to Individual Users or a Group of Users

MigrationWiz improved its functionality to allow license management and assignment for users and groups for Microsoft 365 mailboxes during regular mailbox migrations. This feature can be accessed within your mailbox project by simply navigating to the mailbox project created and selecting the 'Apply Microsoft 365 Licenses' option.

With this enhanced functionality, MigrationWiz customers can seamlessly incorporate license assignments into their regular mailbox migrations, granting them finer control over the backend processes during migration. Customers retain the flexibility to revisit and modify the default license type selection at any time. Furthermore, they can make decisions regarding future license applications during the discovery phase.

To access this feature, follow the steps below.

1. Navigate to the Source/Destination section of the Advanced Options.
2. Select the Apply Licenses to Target Mailboxes during the Pre-Stage Process checkbox in the Destination section.
3. Navigate to the mailbox project and select Apply Microsoft 365 Licenses to enable license assignment.

Shared Mailboxes

Shared mailboxes migrate similarly to a regular mailbox migration.

• Migration with administrative credentials
  From the MigrationWiz dashboard, click on the Quick Add button and enter the email address of the shared mailbox at the Source, and the email address of the shared mailbox at the Destination.
  
  When the migration is performed, it migrates with the administrative credentials added when creating the project. The administrator account must have full access permissions to the shared mailbox to perform the migration.
  
  If you perform a Bulk Add of users, simply include the shared mailboxes in the CSV file that is used to import the mailboxes into the MigrationWiz dashboard.

• Migration without administrative credentials
  From the MigrationWiz dashboard, click on the Quick Add button and enter the email address of the shared mailbox at the Source, and then the login name and password of either the owner of that shared mailbox or an account that has full access permissions to the shared mailbox.
  
  Also, enter the email address of the shared mailbox at the Destination, and then the login name and password of either the owner of that shared mailbox or an account that has full access permissions to the shared mailbox.

The screenshot below using the fictitious acme.com provides an example of how to add the shared mailbox into the MigrationWiz dashboard, for the Destination.

The login name and password can only be added if the MigrationWiz project is created without administrative credentials.

Refer to the Create a Shared Mailbox article from Microsoft for more information about how to create and use shared mailboxes in Office 365.

As with a regular mailbox migration, it is necessary to purchase mailbox migration licenses or User Migration Bundle licenses to perform the migration.

Shared mailboxes make it easy for a specific group of people to monitor and send emails from a common account, like public email addresses, such as info@mining88.com or contact@mining88.com. When a person in the group replies to a message sent to the shared mailbox, the email appears to be from the shared mailbox, not from the individual user.

Shared mailboxes are a great way to handle customer email queries because several people in an organization can share the responsibility of monitoring the mailbox and responding to queries. The customer queries get quicker answers, and related emails are all stored in one mailbox.

Shared mailboxes are also ideal for storing the mailbox contents of terminated employees.

It is not necessary to assign licenses to shared mailboxes in Office 365, except when they are over their storage quota of 50GB.

In the back end, shared mailboxes are identical to user mailboxes. Look at the user list; there will be a user created for the shared mailbox.

Mailbox Size

There is a relationship between mailbox size and data transferred but they can be quite different and cannot be compared directly.​ The size statistics shown on the mailbox statistics page indicate the amount of data transferred over the wire. This typically differs from your mailbox size (as reported by your Source email system) for different reasons including:

• Size calculation: Your Source email system calculates and reports mailbox sizes using proprietary formulas and methods.
• Content conversion: The same data may be encoded using different formats at the Destination (i.e., plain text + HTML MIME parts).
• Protocol overhead: Data, as read from the Source, often includes protocol data such as headers, flags, IDs, and more.
• Data encryption: Unless you configure your connection to use non-SSL endpoints, all data will be encrypted.
• Data compression: Data may be compressed or decompressed during storage or transmission.
• Data encoding: Many communication protocols will encode data (like Base64 encoding, and SOAP encapsulation).

Also, some items may not be migrated or may fail to migrate, depending on the error count specified on your project.

If you are trying to compare mailbox sizes because you are looking for missing items, click here.

Add Mailbox to Existing Project

1. Sign in to your Migratio​nWiz account.
2. If you do not see your projects listed, click on the Projects​ section.
3. Click on the name of your Project in the list. 
4. Click on the Add button.​​

Sent Items Migrated to the Wrong Location

This article applies to mailboxes whose Source "Sent Items" folder was successfully migrated, but whose location at the Destination is different from the expected one.

The IMAP protocol only identifies the "Inbox" folder as a system folder. There is no clear identification of other system folders such as "Sent Items", "Deleted Items", and others.

For example, a "Sent Items" folder may be labeled as “Sent Items”, “My Sent Items”, “Sent”, “Sent emails”, “Courrier Envoye”, ”Sendte emails”, and so forth. There is no reliable way for us to detect if a specific folder is a Sent Items folder. For this reason, we map folders by name.

​​However, we support folder remapping as an advanced feature. To implement specific folder mappings:

1. Go to Advanced Options. To enter Advanced Options within the new MigrationWiz interface, select your project name, then click on Edit Project at the top left, then click on Advanced Options at the bottom right.
2. ​Within the Support Options section, specify the following:

   FolderMapping="^SourceFolder->DestinationFolder"

   Example:

   FolderMapping="^My Sent Emails->Sent Items"

3. ​​Click on Save Options.
4. Click on Save Project.

The expressions on the left and the right are regular expressions.

Migrating Permissions

Folder permissions are migrated using the following approach:

• First, MigrationWiz tries to match the source primary SMTP email address to the destination primary SMTP email address.
• Next, MigrationWiz tries to match the source display name to the destination display name. If more than one match is found on the destination display name, a failure occurs and the permissions are not assigned to that particular UserID.

By default, MigrationWiz only migrates Mailbox Folder Permissions for System folders. To migrate permissions on folders that were created by users, the Advanced Option must be set to MustMigrateAllPermissions=1 in your project.

Merging Mailboxes

If you intend to merge several email accounts that you have been managing separately into a single email account, you can do it via MigrationWiz, by migrating all Source mailboxes at the Destination where they are mixed. Consider that you need to purchase as many licenses as Source mailboxes you want to merge.​

You need to perform the following steps:

1. Create a Project, and add a mailbox to migrate from the first Source mailbox to the single Destination mailbox.
2. Submit the migration from the first mailbox to the Destination mailbox.
3. Wait until the migration has been completed.
4. Add a mailbox to migrate from the second mailbox to the same Destination.
5. Open Advanced Options.
6. Under Support, checkmark the Do not search destination for duplicates button.
7. Submit to migrate from the second mailbox to the single Destination mailbox.
8. Wait for completion.
   

   Important

   If you have more than two accounts, repeat Steps 4 through 8. Requiring two or more licenses, one for each Source mailbox.

You can also migrate the Source mailboxes into individual subfolders at the Destination as described in Folder Filtering and Mapping.

Migrating Suggested Contacts and Autocomplete Lists

It is important to understand the difference between Autocomplete Lists and Suggested Contacts.

Autocomplete Lists

When email addresses are typed in, Outlook remembers them and can offer autocompletion when adding recipients to a new email message. The Autocomplete List stores email addresses in a server-side hidden file. Therefore, those contacts remain accessible when a user has multiple computers running Outlook 2010 or later.

If you are using the DeploymentPro product to automate the configuration of Outlook profiles, Autocomplete Lists are migrated over to the new profile, as part of the process. The DeploymentPro Guide provides more information on the steps to follow to run DeploymentPro projects. If you are using DeploymentPro, you do not have to manually migrate these.

Suggested Contacts

Suggested Contacts is a special contact folder introduced with Exchange 2010 and was removed in Exchange 2013. This folder creates contacts for each new address a user sends an email to.

Summary

This table shows which type of contacts are supported by Outlook/Exchange, depending on the version.

• Autocomplete Lists:

• From Exchange Server 2003 / 2007 (.Nk2 file): MigrationWiz does not migrate these. This process must be done manually.
• From Exchange Server 2010 / 2013 / 2016 (server-side file): MigrationWiz does not migrate these. The DeploymentPro product migrates these. If you are not using DeploymentPro, the process must be completed manually.
• Suggested Contacts:
• From Exchange Server 2003 / 2007 / 2013 / 2016: Not applicable.
• From Exchange Server 2010: Are migrated by MigrationWiz.

Autocomplete Lists and Suggested Contacts cannot be migrated if the Source Exchange server is unavailable.

Finding Large Items 

The size item limit on the Destination may be lower than the Source. This results in migration failures for those items that are larger than the limit on the Destination.

Before you start a migration, it is possible to identify the items that will fail to migrate by doing a mailbox search for large items on the Source.

• This is an end-user approach, which requires each end user to perform these steps. 
• This article includes instructions for Outlook clients and G Suite webmail clients. Refer to the option that matches your client.

Option 1: Using Outlook Client

1. Create a new search folder.
2. In the resulting dropdown list, scroll down, select Large mail, and click Choose...
3. Change the number to the item size limit on the Destination (e.g., 25000) and click OK twice.

You have a new folder under Search Folders, that displays all the emails that are larger than the selected size.

Option 2: Using G Suite webmail client

1. Access the G Suite Gmail website.
2. On the Search box, type the item size limit on the Destination (e.g., 25000000) and click the search icon.

The value entered in the search box must be in Bytes.

Configure Users Who No Longer Exist in the Source Tenant

MigrationWiz allows customers, with long-running projects, to quickly tag inactive accounts on the source tenant and remove them (if needed) with just one click, to ensure the accuracy of their user lists.

This option is available for all mailbox migrations in the Quick Add and Bulk Add options, allowing you to choose the mailbox status as Active or Inactive. 

Use the Quick Add option when adding one mailbox item at a time. To configure the status, scroll down to the Mailbox Status Options section and select the Active or Inactive status from the dropdown list.

Otherwise, use the Bulk Add Items to import and configure more than one mailbox at a time using a CSV file. After selecting the CSV file, set the mailbox status in the User Status column by choosing the Active or Inactive status from the dropdown list.

Also, the Bulk Add Items feature allows you to choose the items to migrate from your database.

You can check the checkbox next to them or apply any of the following rules:

• Only newly detected active mailboxes will be migrated, if you want to migrate only the active mailboxes in the CSV file.
• All newly detected mailboxes will be migrated, if you require to migrate all the new mailboxes regardless of status in the imported CSV file.
• Old and new detected mailboxes will be migrated, if you want the entire data from the imported CSV file.
  

  Important

  In this case, the already migrated existing mailboxes on the destination tenant are overridden with the current updated information.

Rediscover Items

MigrationWiz provides you with a new brand feature that allows you to detect additional mailboxes that were added to their Microsoft Entra ID scoping group all the mailboxes at the source tenant, besides providing you with a downloadable CSV file with all the important data about the migration, such as email, login name, and status of source accounts in the tenant.

Bulk Address Change

Domain Name

There are two ways you can bulk update the domain name in the email addresses of migration mailboxes:

• You can use the Change Domains button in MigrationWiz.
• You can download and run the Change-MW_ExportAddresses and Change-MW_ImportAddresses PowerShell scripts attached at the bottom of this article. 

Why might it be necessary to change the Source or Destination address of all your Users on a MigrationWiz Project? 

• If you are performing a tenant-to-tenant migration while keeping the same domain name, and you started the migration using the vanity domain on the Source addresses, we recommend using .onmicrosoft.com addresses for both Source and Destination addresses to avoid this.
• If you just ran Autodiscover on MigrationWiz to discover all your Source mailboxes, and you are migrating into a different Destination email domain.

These examples are two among others that might make it necessary to have to change those addresses.

Use the Change Domains button

MigrationWiz now provides the option of doing a bulk update of email addresses on both the Source and Destination computers, where the change is of the address domain.

When you click on the Change Domains button, the box opens to allow you to bulk change the domain associated with mailboxes on the Source or Destination.

Full Addresses 

Use the BitTitan SDK PowerShell Script

• If the BitTitan SDK is not installed on your computer, the first step is to download and install it. Our SDK includes the PowerShell and the Management Console modules. The pre-requisites and download link for the SDK can be found here: Install the BitTitan SDK
• Download the PowerShell script(s) required to make the bulk changes. Links for downloading the scripts can be found at the bottom of this KB: 
  • The Change-MW_ImportAddresses script changes all Destination addresses
  • The Change-MW_ExportAddresses script changes all Source addresses.

• Both scripts make changes based on a CSV file, that needs two columns, as shown below:
• You must name column A as "UserPrincipalName" and column B as "NewUPN", because those are the names hard-coded in the script.
  • List all the current addresses in the project in column A.
  • List all the new addresses, with the new domain name, in column B.

You can obtain those addresses by exporting them via PowerShell when connected to the Source or Destination system (i.e., via the On-Premises Exchange or the Exchange Online PowerShell).

Follow these steps to run the PowerShell scripts:

1. Once you run the script, enter your MigrationWiz credentials in the prompt.
2. Enter the MigrationWiz project name and the location of your CSV file.
3. Let the script run and change all the Source or Destination addresses, as defined in the CSV file.

"Sent Items" Folder