Frequently Asked Question
Why does my AOMEI Backupper NAS backup fail with a username, password or access-denied error?
QUICK ANSWER
Check the exact share path and the credentials saved for the backup task. Being able to browse the NAS in your desktop session does not prove the scheduled backup can use the same access.
Applies to: AOMEI Backupper jobs writing to a supported NAS/network share, including after a NAS password or permission change.
Work through these checks
- Record the destination as a full network share path and check that the NAS and share are reachable from the backup computer. A mapped drive letter can depend on the signed-in user's session.
- Check the dedicated backup account's share and folder permissions. From an appropriate authorised session, test creating, reading and deleting a harmless test file in the intended folder; never test by deleting backup images.
- Review the network credentials stored in the task or supported share-management interface. Update the saved credentials after an account/password change and check for conflicting connections using another account.
- Compare a manual run with the scheduled run. If only the schedule fails, review its execution context, network availability and permissions with the administrator. Keep the NAS account limited to the required backup location.
Confirm the result
Run a small supported backup to the intended folder, then test the scheduled execution and image check. Confirm that the job writes new data using the intended account.
Before going further: Do not enable SMB1, guest access or broad administrator permissions to bypass an authentication error. Preserve the existing backup chain while correcting access.
If you need help
Include these details in your ticket: Backupper/NAS version, redacted share path, manual-versus-scheduled result, error code and whether credentials or permissions changed recently. Never include passwords.
Updated 261107