Software Distribution for IT Support Companies & MSP's

Support queries shared: Windows image backup reaching 2TB limit

We’ve seen a few issues recently where a Windows image backup job has failed due to the destination drive partition being larger than 2TB. Unfortunately the errors generated can differ, so it can be sometimes difficult to spot.

We recommend that if you are using the Windows imaging engine within BackupAssist, you use destination devices that are 2TB or smaller, and the same applies to iSCSI destinations.

If you are trying to backup more data than can fit on a 2TB destination, consider splitting the job up into multiple parts. For example, run one Windows Image job to do a bare metal backup of the system drive and system reserved partition, and a second job to take care of any data partitions.

I recently worked with a customer who had around 3TB of virtual machine data when using Hyper-V. In cases like that it’s advisable to split the jobs even further so BackupAssist backs up half of the VM’s with one job and the rest with another – each job running to a separate destination that is 2TB or less. A third bare metal backup looked after the system volume.


  1. Paul

    Very interesting. I have a few clients approaching 2TB especially with Hyper-V servers. Have you tried partitioning a 3TB USB drive (a 2TB and a 1TB partition) and running the 2 seperate backup jos to seperate partitions? any reaosn why this wouldn’t work? This would save the client having to change 2+ disks every day which could be annoying for their offsite strategy.

    • neilzensoftware

      Hi Paul,
      Thanks for your comments.

      Yes you can partition one destination drive in this way. Then create two jobs to backup half of the VMs each. This will keep your destination backup file well below the 2TB limit. After some more investigation I think the main issue is having any single backup “VHD” file created that is greater than 2TB, and not actually the destination drive being say 3TB storing two 1.5 TB backup “VHD” files. If you are able to test this scenario I would be very interested to know if you see the same using one single 3TB destination disk running two backup jobs that are less than 2TB each.

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