Backups failing with either one or both of the following errors;

Cannot authenticate to the network path: \\machine-ip\share on domain “domaine-name” with user “user-name”

[Windows Error 5]: Access is denied.

Access denied while moving the file:

\\machine-ip\share\altaro-repository\BackupData.dat.locked to \\machine-ip\share\altaro-repository\BackupData.dat (or vice versa)

Windows Error 5]: Access is denied.


This error occurs when certain backup data files that Altaro would need to modify during a backup/restore are found to be in use or previously locked by a 3rd party process at the time.


  1. The first thing that must done to resolve this issue would be to address the Altaro database file that would have been “.locked”
    1. Ensure no backups/restore jobs are currently running

    2. Navigate to the backup location and perform a quick search for the extension “.locked”

    3. Once that’s done perform a manual backup of the Virtual Machine to confirm that the issue has been resolved. Should the manual or subsequent backups also fail with the same errors, then the source of this issue must be addressed, by following the next steps.

  2. Any file level scanning software, especially an Antivirus automatic scan of the Backup Location

  3. Make sure 'Offline Caching' is Disabled if the backup location is a Windows Share

  4. Make sure Opportunity Locks (Oplocks) are disabled if the backup location is a NAS

  5. Make sure that "Enables disk standby mode: The status LED will turn off if there is no access within" is disabled

  6. And lastly please ensure you are running the latest build of Altaro VM Backup