When performing a migration or reset using Quest On Demand Migration, one or more of the following symptoms may occur:
The primary mailbox reset completes, but the archive mailbox reset repeatedly fails.
The primary mailbox reset fails.
The Reset Mailbox task in On Demand becomes stuck or does not progress.
Missing folders persist after previous failed migration attempts.
Archive re-migration attempts fail or terminate prematurely.
The archive mailbox does not perform a full reset or re-sync.
These symptoms occur even though the Reset operation for the primary mailbox works normally.
The issue is caused by a Recoverable Items quota overrun in the archive mailbox within Exchange Online.
Key points:
The Recoverable Items folder supports up to 100GB, but the Purges subfolder has a hard limit of 30GB.
When the Purges subfolder reaches 30GB, Exchange Online blocks further deletions.
The Mailbox Reset API used by Quest On Demand cannot proceed because Exchange cannot clear required system folders.
The Managed Folder Assistant cannot process retention cleanup due to the quota exhaustion.
This is a limitation of Exchange Online storage architecture, not a defect in Quest On Demand Migration.
To restore functionality and allow Quest On Demand to complete the mailbox reset, perform the following steps in Exchange Online:
1 . Lower the Deleted Items Retention Temporarily:
Set-Mailbox -Identity <user> -RetainDeletedItemsFor 1.00:00:002. Run the Managed Folder Assistant (MFA)
Start-ManagedFolderAssistant -Identity <user>3. Allow MFA to run for 30–120 minutes.
Once successful, the Recoverable Items → Purges size will decrease below the 30GB limit.
4. Retry the Mailbox Reset in Quest On Demand
With the quota issue resolved, the archive reset should now complete successfully.