1408 - M365 backup scan fails with error "User's mysite not found"

Symptom

The scanning task in a Microsoft 365 backup fails with the error "User's mysite not found". This can happen for OneDrive, Exchange, SharePoint, or Teams.

Cause

In Microsoft 365, a My Site or mysite is a personal site for an individual user in an organisation. A user's mysite is not created automatically when a licence is assigned to them; it is only provisioned when the user logs into OneDrive for the first time. Our system cannot scan unprovisioned accounts for backup, so if a specific account's user has never logged into OneDrive, our system will be unable to backup the account and you will see this error.

Solution

To prevent this error, follow the steps below: 

1. Check that the affected account is licensed correctly (e.g. not Personal or Family Edition).

2. Ask the account's user to sign into OneDrive (onedrive.com or via the Microsoft 365 portal) at least once. This will trigger automatic provisioning of their personal site.

• If you are a global admin or SharePoint admin, you can also pre-provision user OneDrives in bulk using the PowerShell command:
  Request-SPOPersonalSite -UserEmails @('user@domain.com')
• If the user is no longer active or does not require backup, remove them from the OneDrive backup selection in the RedApp.

3. Allow up to 24 hours for provisioning to complete across the tenant, then initiate a new backup from the RedApp.

If the problem persists, log a support ticket.