PST to Microsoft 365 Migration Guide

This is the complete onboarding task flow for migrating PST files (Outlook Data File) into Microsoft 365 mailboxes.


MigrationWiz is a migration solution (not a synchronization solution) and will NOT propagate updates, deletes, or moves of the items previously migrated in the first migration pass because we do not have “live” monitoring of changes (as with a sync agent) and we cannot handle scenarios such as conflict resolution without user interaction.

MigrationWiz supports the capability to share migration projects across a Workgroup. When the Project Sharing feature is turned on, all Agents besides those who are Inactive can view all migrations projects. For more information, visit Project Sharing in MigrationWiz. 

The maximum file size for migration through MigrationWiz varies by migration type and environment, but may never exceed 60GB.

First migration?

We’ve created a guide on scoping, planning, and managing the migration process for your use. If this is your first migration, we recommend reading this guide carefully.

For more information on how to set up a project using Azure Storage, read the Azure for MigrationWiz article.

The key difference for PST migrations, when compared to standard mailbox migrations, is that the PST files need to first be discovered and then uploaded to a secure Azure Storage account, before they can be migrated into the mailboxes on the Destination, using MigrationWiz.


Review and meet the following requirements for PST files:

  • PST files need to be in Outlook 2003 (or later) format.
  • PST files cannot be corrupted. We do not provide an automated solution for repairing or migrating corrupted PST files. In case there are corrupted PST files, fix them before performing a migration.
  • If UploaderWiz is installed:
    • Windows Vista or later is required for desktops. Mac OS is not supported.
    • Installed .NET 4.6 or later.
    • Permission to run a command prompt as Administrator.

The key difference for PST migrations, when compared to standard mailbox migrations, is that the PST files need to first be discovered and then uploaded to a secure Azure Storage account before they can be migrated into the mailboxes on the Destination, using MigrationWiz.


We recommend that you purchase User Migration Bundle licenses for this migration scenario. User Migration Bundle licenses allow the performance of multiple migrations with a single license. For questions on licensing, visit MigrationWiz Licenses.

To use your license by following the next steps:

  1. Purchase Licenses.
  2. Create a Customer.
  3. Apply Licenses.
  4. Review Considerations.
Purchase Licenses Create a Customer Apply Licenses Considerations

Purchase licenses by following the steps below:

  1. Sign in to your BitTitan account. 
  2. In the top navigation bar, click Purchase.
  3. Click the Select button and choose User Migration Bundle licenses.
  4. Enter the number of licenses you want to purchase. Click Buy Now.
  5. Enter a Billing address if applicable.
  6. Click Next.
  7. Review the Order Summary and enter a payment method.
  8. Click Place Your Order.


  • App passwords are not supported for the Microsoft 365 endpoint. 

Migrated Items

Migrated Non-Migrated
PST Files from your Azure storage
  • Folders
  • Email
  • Contacts
  • Calendars
  • Tasks
  • Journals
  • Notes
PST BitTitan Storage 

PST Files are uploaded to BitTitan Storage using the UploaderWiz tool.

  • Folders
  • Email
  • Contacts
  • Calendars
  • Tasks
  • Journals
  • Notes

Prepare the Azure Environment

  1. Estimate Azure storage costs. This step is optional but is useful to provide the customer with upfront storage costs ahead of time. 
  2. Buy an Azure subscription, or use the free one-month trial. The trial option is only viable if you are performing a very small migration. 
  3. Create an Azure storage account. You will need to set up a STORAGE (General Purpose v2) account rather than a storage blob.
  4. Take note of the storage account name and the primary access key. (In Azure, from the storage screen, click Manage Access Keys at the bottom of the screen). These need to be entered into the MigrationWiz migration project when specifying the destination settings. 

To create the Azure storage account, follow the steps below:

  1. Visit the Azure portal.
  2. Click Storage accounts.
  3. Click Create.
  4. Select the Subscription and create a new Resource group or use a current one.
  5. Name the Storage account.
  6. For Region, select a geographic region for the storage account.
  7. For Performance, select Standard general-purpose V2 account.
  8. In the Redundancy field, select Locally-redundant storage (LRS).
  9. Click the Review button.
  10. When the validation ends, click the Create button.
  11. Once the deployment of the storage account is complete, click the Go to resource button or open up the home page for the new storage account.
  12. In the Security + networking section of the left sidebar, click on Access Keys.
  13. On a notepad, copy the Storage account name and the key1 and save them.

Now the storage account appears in the storage list.

Prepare the Destination Environment

Create the Admin Account

  1. Create a user in Office 365.
  2. Connect to Exchange Online by using remote PowerShell.
  3. Type the following command, and then press Enter:
    Get-Mailbox -ResultSize unlimited -Filter {(RecipientTypeDetails -eq 'UserMailbox') -and (Alias -ne 'Admin')} | Add-MailboxPermission -User -AccessRights fullaccess -InheritanceType all

After you perform these steps, the specified user will be able to access all user mailboxes in Microsoft 365. The user will be able to view the contents of the mailboxes from either Outlook or Outlook Web App.

Set up Accounts in Microsoft 365

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

Modern Authentication Requirements

The steps listed in the Obtain Client and Tenant ID Settings for Mailbox and Exchange Online Migrations section of the Authentication Methods Migrations KB apply to both the source and destination tenant when they are Exchange Online, in regards to Exchange Web Services (EWS) in mailbox, archive mailbox, and public folder projects. Use a Global Administrator for the configuration steps.

Please review the documentation before preparing the destination.

Prepare the Tenant to Send & Receive Large Items

We do not impose any limit on item/attachment sizes. However, large items/attachments can fail to migrate because of external factors.  There are two considerations:​

What is the maximum attachment size allowed by the Destination system? 

  • Most email systems impose size limits. For example, if the Destination system has a 30MB limit, any item/attachment larger than 30MB will fail to migrate.

What is the connection timeout for the Source and Destination system? 

  • ​​For security reasons, most email systems close opened connections after a predetermined amount of time. For example, if the Destination system only has 512Kbps of network bandwidth and closes connections after 30 seconds, we may be unable to transfer large items/attachments before the connection is closed.

MigrationWiz automatically makes multiple attempts to migrate large items. Upon completion of a migration, you may resubmit it in error retry mode to try to migrate failed items. This is always free of charge.

When migrating from or to Office 365 use the steps provided here to increase the Max Send and Max Recieve quotas, Change message size limits in Office 365.

Discover PST Files and Upload to Azure

Discover PST files on the network, and upload them into Azure.

MigrationWiz Steps

Create a Personal Archive Migration Project

  1. Click the Go to My Projects button.
  2. Click the Create Project button.
  3. Select Personal Archive as the migration type.
  4. Click Next Step.
  5. Enter a Project name and select a Customer.
  6. Click Next Step.


Endpoints are now created through MigrationWiz, rather than through MSPComplete. The steps for this section outline how to create the endpoints in MigrationWiz.

If you are selecting an existing endpoint, keep in mind that only ten endpoints will show in the drop-down. If you have more than ten, you may need to search. Endpoint search is case and character-specific. For example, Cust0mer will not show up if the search is customer. We recommend keeping a list of endpoints you have created, along with any unique spellings or capitalization you may have used.

You may either use existing endpoints or create new ones. 

Client Secret for Microsoft 365 Endpoints

For all Microsoft 365 Endpoints mailbox migrations (including archive migrations), MigrationWiz adds the Client Secret field, which is not always mandatory. It will depend on the permissions of the user account that performs the migration. Please review the following information before the creation of your M365 endpoints.

  • The client secret value is not mandatory if you use delegated permissions. Please leave the Client Secret field empty.

  • The client secret value is mandatory if you use the RBAC approach for application impersonation.

  • If you already have an admin account with the Impersonation role enabled (not using the RBAC approach) the client secret value is not mandatory. Please leave the Client Secret field empty.

Create a Source Endpoint

  1. Click Endpoints.
  2. Click Add Endpoint.
  3. Select PST.
  4. Enter Storage Account Name and Access Key in the fields provided. When entering the Azure Storage Account Name for the source endpoint, only numbers and lowercase letters can be used. If you enter an upper case letter, your migration will fail.

Create a Destination Endpoint

  1. Click Endpoints.
  2. Click Add Endpoint.
  3. Enter endpoint name.
  4. For the endpoint type, select Office 365.
  5. Fill out the required fields.
  6. Complete the Application (client) ID, the Directory (tenant) ID, and the Client Secret fields, otherwise, you cannot save your project.

    Destintation Settings.png

  7. Click Next Step.


When configuring the destination endpoint, do not forget to complete the client ID and the tenant ID fields for the Destination endpoint, otherwise, you cannot save your project migration.

Once the information has been provided for both, the source and/or destination endpoint, and the customer selects Save and Go to Summary, MigrationWiz performs an endpoint validation check for the Microsoft 365 endpoint.

This validation tests the administrator credentials entered into the project and the Modern Authentication setup only. If there is an issue, the screen redirects to the endpoint and provides an error message or flyout that can be selected for more information regarding the error.

Common Errors when Configuring Your Endpoint

For more information, review the AADSTS700016, AADSTS90002, and ADDSTS50126 issues on the Common Errors Using Modern Authentication page.

Add Users

Add the user accounts that will be migrated to the project.

Advanced Options

The following sections describe the tabs available for Advanced Options in this kind of migration.

Support Tab

Consider that each Support Option includes the "=" character and is to be entered under the Support tab in the section named Support Options.

Add additional blank fields for new Support Options by clicking on the "+" button. In case you want to delete a field click the trash can icon.

AO Support Tab.jpg

Optional Settings

  • PSTCustomEndpointSuffix=Azure URI This advanced option is only needed when uploading your PST files to a specific Azure data center, using the UploaderWiz optional parameter of azurelocation=gov, ger, or china. The Azure URI needs to be changed to one of these values:
    • (China)
    • (Germany)
    • (government)
  • Folder Mapping. Folder mapping is optional, but you can control the mapping of folders on the destination by using regular expressions. Read the Folder Filtering & Mapping in MigrationWiz article for more information.


     By default, MigrationWiz mirrors the folder structure that exists on the Source when migrating to the Destination. When a migration starts and you are taking the default folder mappings (that is, a single folder at the root), MigrationWiz creates the Destination folder based on the item type of the first item migrated. If the first item is a calendar item, then the Destination is mapped to the root of the calendar folder. You can control this by migrating item types in batches (mail items, calendar items, etc.), with each item type migrated in a separate migration pass.

Default Options for Microsoft 365 Endpoints

By default, some fields are view-only. In other words, you cannot edit or remove them from the support options page. To edit them, you need to edit the source or destination endpoint of your project.

Among these default options, you can find ModernAuthClientIdExport, ModernAuthTenantIdExport, ModernAuthClientSecretExport, ModernAuthClientIdImport, ModernAuthTenantIdImport, and ModernAuthClientSecretImport. 

The support options above are required when configuring your endpoint.


Keep in mind that the ModernAuthClientSecretExport and the ModernAuthClientSecretImport support options are text-masked.


You cannot update the default Advanced Options, in case you try to modify or add new ones the following message arises.
Duplicate Support Option.png

Performance Tab

  • Set the preferred BitTitan data center. For the fastest migration speeds, select the data center that is closest to your Microsoft 365 Destination tenant. Read the BitTitan - Data Security and Privacy Policy article for more information.

Source/Destination Tab

  • Set the bucket name to "migrationwiz". If you are using your own Azure storage and uploaded your PST files into a container that has a different name, change the bucket name to "migrationwiz". If the container name and bucket name do not match, you will get an error when trying to import your PST files.
  • Under Destination, choose whether to ingest the PST files into mailboxes or archives.
  • Enable impersonation at Destination by selecting the check box Use impersonation at Destination.

Import PST files

Import PST files into the MigrationWiz PST archive project.

  1. Click the Autodiscover Items bar.
  2. Click the Start Autodiscover button.
  3. Once the PST files have been discovered, click the green + Import Items.
  4. If 0 items are discovered, a common mistake is that the Source/Bucket Name under Project Advanced Options has not been set to the correct Azure container name.

Choose Destination Mailbox

Choose which Destination mailbox to inject each PST file into.

The owner's email address should be displayed under the "Destination Email" column.
If is displayed as the Destination email address instead of the actual owner's email address, click the Edit Item (pencil icon) to the right of the row. Then, under the Destination Email Address field, enter the mailbox that this file will be ingested into.

If you have multiple PST files to migrate into a single mailbox, click the pencil icon next to the individual migration item. Then, under Source PST Path, click the Add button (the +) to add the additional PST path(s).

Run Verify Credentials

  1. Open the Project containing items you wish to validate.
  2. Select the items you wish to validate.
  3. Click the Start button in your dashboard.
  4. Select Verify Credentials from the drop-down list.

Once complete, the verification results will be shown in the Status section.​ 

Start migration

  1. Select the users.
  2. Click the Start button from the top.
  3. Select Full Migration.
  4. Click Start Migration.

Run Retry Errors

Look through the user list and click any red "failed migration" errors. Review the information and act accordingly.

If problems persist, contact Support.

Post Migration

Optional (does not apply to Microsoft storage): Delete the Azure blob container that was created during the upload to Azure. This will prevent incurring post-migration Azure costs for these containers. Be careful and delete only the container created for this migration project.

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