The backup fails with a Microsoft VSS umbrella error, "A problem with Windows Shadow Copy was detected".

Unable to get a list of the VMs files which need to be backed up using the VSS Provider. (ALTERR_JOBBATCHER_011)


This error is caused whenever the VSS writers on the host machine take long to populate, which might be due to snapshots/checkpoints running on the VM. A missing VSS provider, unresponsive VSS services and missing Altaro VM Backup components can also contribute to causing such a backup failure.


  1. Ensure no VMs are running on a checkpoint/snapshot. If so, please delete them and try the backup again.

  2. Run the command vssadmin list writers and monitor how long it takes for all writers to be listed. This should normally take no more than 5-6 seconds.

  3. Run the command vssadmin list providers and check that both the 'Microsoft File Share Shadow Copy Provider' & 'Microsoft Software Shadow Copy Provider' are listed

  4. Restart the following services:
    • All Altaro services
    • Volume Shadow Copy service
    • Microsoft Software Shadow Copy Provider service
    • Hyper-V Virtual Machine Management service (VMs will NOT be affected and will remain online)

  5. Uninstall Altaro VM Backup and re-install, this time by using the right-click >> Run as Administrator option for elevated privileges. (All settings will be kept, and no reboot is required)

If all else fails, kindly check that all Windows Updates are installed on the host, including optional ones, then give the host a reboot after installing the Windows Updates and re-try the backup.