Sometimes a file is locked and Altaro cannot access the file, causing the backup to fail. The error displayed may look like this:


To fix this, one easy way is to restart the NAS, but this may not be feasible in some situations. In such cases, we need to log in to the NAS and unlock the file.

To do this, take note of the folder name GUID that precedes the locked file from the Altaro backup server.


Log in to the NAS and click on the Shell menu to get a command shell into the NAS.



Enter the command: SMBSTATUS to get a list that will display the SMB files being accessed. Locate the locked file by searching for the file name and GUID folder. You will notice it has a PID (Process ID) as shown below.


Enter the command: KILL –9 PID


Once the process is dead, restart the backup job.


  1. D Munz


    The real question here is why is this even happening? I am experiencing the same problem.

    • Reply

      Hello D Munz,

      One of the great things about Altaro is their support, give them a call or chat and they will help you figure out why it’s happening. In my case, the cause was the initial full backup had become corrupted due to bad media and subsequent backups were failing and leaving the file open. The issue was caused by the backups failing, not vice-versa as I had thought. I recreated the initial full backup on another NAS (also TrueNAS) and after it completed successfully, the problem went away.

Leave a comment

Your email address will not be published. Required fields are marked *

error: Sorry, copy/paste is disabled
Skip to content