Syncovery Support Forum

Hello,

I am running Syncovery 9.22 Build 115, recently updated from Syncovery 8.5, on Windows Server 2019. I am backing up two running Hyper-V virtual machines once per week with versioning. The .vhdx files are large, 115 GB and 227 GB. Roughy, 1 of 4 backups are corrupted files failing CRC and cannot be copied further. I believe I recently started observing this when I went from Server 2012 to Server 2019. I have tried with VSS both on and off and it seems to make no difference. If I manually stop the VM's and run the backup, it works without issue. Should I try using Windows API copying with VSS on? Or something different?

Thank you.

Hello,
what kind of CRC check are you referring to? Can you mention the exact method with which you check the files and the exact error message that you get?

This issue occurs only with VM backup files made by Syncovery, nothing else. All drive | Properties | Tools | Error Checking | Check runs have reported no problems. I get a CRC error when running Syncovery or DOS copy command trying to copy a Syncovery backup of certain .vhdx files. It doesn't matter where I try to copy it to, a different file name on same drive or to a different drive. Syncovery logs an error like this: 10:07:24 PM - Read error at position 68 GB: thefilepath.vhdx. DOS copy reports something similar. chkdsk /f reports no problems. chkdsk /r reports something like:
Stage 4: Looking for bad clusters in user file data ...
Windows replaced bad clusters in file 10BD0
of name ...

And I just realized this probably means the drive is going bad and the sheer size of the .vhdx files mean they are most likely to encounter the issue. Time to order a new one. Thanks for being a sounding board.

Hello,
yes, CRC errors mean a failing hard drive. It's possible that some copying circumstances may make CRC errors more likely (such as a lot of disk seeks), but in general it is a hardware problem.