Archive Migration fails due to Source and Target Mailbox having the same ArchiveGUID (4373754)

Resolution 1: For Hybrid Environments

To resolve this issue the target archive needs to be disabled, purged and recreated. The process to do this is as follows 

1. Remove litigation hold from the mailbox (Wait 60 mins after doing this before proceeding)
2. Disable the Archive Mailbox, can be done within the M365 Admin or using Powershell
   • Disable-Mailbox -Identity <username> -Archive
3. Purge the Archive - Set-Mailbox -Identity <username> -RemoveDisabledArchive

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4. Clear the msExchArchiveGUID from the target account in the target AD Domain

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5. Sync those changes to Azure by running a delta sync in AADConnect
6. Enable the Archive of the account in O365 - Enable-Mailbox -Identity <username> -Archive
7. Confirm the archive is created with a new guid - get-mailbox -Identity <username> | select archiveguid
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8. Go to ODM, Accounts, select affected account for that mailbox, Discovery, Refresh Selected
9. You can now run the Archive migration task and the task will run successfully.

Resolution 2: Cloud Only Environments

The archiveguid should never be the same in this scenario.  If the archive was created after the ODM accounts discovery task there is a possibility this error could be seen in the ODM Events. To resolve the issue, perform the following steps within ODM.
 

1. Access the Accounts module
2. Select the impacted account(s)
3. Click Discovery and choose Refresh Selected Accounts
4. Create and run a new Mailbox Migration