AOMEI Backupper Backup Failed: How to Fix It

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A failed backup in AOMEI Backupper almost always comes down to one of four causes: not enough storage space, a blocked backup service, a disconnected drive, or a path problem. Here’s how to check each one.

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Check the Destination Drive Has Enough Space

This is the single most common cause of a failed backup. Check how much free space is on the drive you’re backing up to, and compare it to the actual size of what you’re backing up. If it’s close, that’s likely the problem, not a software bug.

Confirm the External Drive Is Still Connected

If you’re backing up to an external or USB drive, check that it’s still plugged in and that its drive letter hasn’t changed. Windows sometimes assigns a new letter to a drive after a restart or reconnect, and a backup job set up for the old letter will fail even though the drive is right there.

Fix a “Failed to Enable Backup Service” Error

This specific error usually means the background service AOMEI needs to run isn’t starting properly. A few things to check:

• Open Windows Task Manager and confirm the AOMEI backup service is actually running.
• Check whether Windows Defender’s ransomware protection is blocking it, and add AOMEI Backupper as an allowed app if so.
• If the software was installed to a folder with a semicolon in the name, this can specifically break the service. Reinstalling to a normal folder path fixes it.
• If nothing else works, uninstalling and reinstalling the software resolves this error in most cases.

Check for Files Locked by Another Program

A backup can fail partway through if it hits a file that’s actively open and locked by another program, like a database file in use, an open document, or a file being synced by a cloud storage app at the same moment. Close any programs you know are actively writing to files in the backup source before running it again, and if you’re backing up a folder that syncs with a cloud service, pausing that sync during the backup avoids the two processes fighting over the same files. AOMEI Backupper’s current versions include a “hot backup” mode designed to work around locked files on a running system, which is worth confirming is enabled if this keeps happening.

Check the Backup Path Isn’t Too Long

Windows has a limit on how long a file path can be. If your backup destination is buried in many nested folders with long names, the path itself can be the problem. Try backing up to a shorter, simpler folder path closer to the root of the drive.

Try a Test Backup on a Small Folder First

If you’re not sure which of the above is causing it, back up a single small folder to the same destination as a test. If that works, the problem is likely the size of your original backup versus available space. If the small test also fails, the problem is more likely the service or the destination itself.

See AOMEI Backupper’s disk and backup tools if you’re deciding whether it’s the right fit for your setup.

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