Cyclic redundanty check error on backup


The last week I’ve been getting this error a lot and I’m wondering if there’s a way to fix it besides deleted the backup DB and restarting.

I’ve tried repairing and recreating the DB but that hasn’t helped.
When I run the backup manually it seems to work though, which is weird. It always seems to fail on a scheduled backup.

Any tips?

This is the stacktrace I’m seeing in the logs related to the error message:

System.IO.IOException: Gegevensfout (cyclische redundantiecontrole) bij Duplicati.Library.Main.AsyncDownloader.AsyncDownloaderEnumerator.AsyncDownloadedFile.get_TempFile() bij Duplicati.Library.Main.Operation.CompactHandler.DoCompact(LocalDeleteDatabase db, Boolean hasVerifiedBackend, IDbTransaction& transaction, BackendManager sharedBackend) bij Duplicati.Library.Main.Operation.DeleteHandler.DoRun(LocalDeleteDatabase db, IDbTransaction& transaction, Boolean hasVerifiedBacked, Boolean forceCompact, BackendManager sharedManager) bij Duplicati.Library.Main.Operation.BackupHandler.CompactIfRequired(BackendManager backend, Int64 lastVolumeSize) bij Duplicati.Library.Main.Operation.BackupHandler.<RunAsync>d__19.MoveNext() — Einde van stacktracering vanaf vorige locatie waar uitzondering is opgetreden — bij System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() bij CoCoL.ChannelExtensions.WaitForTaskOrThrow(Task task) bij Duplicati.Library.Main.Controller.<>c__DisplayClass13_0.<Backup>b__0(BackupResults result) bij Duplicati.Library.Main.Controller.RunAction[T](T result, String& paths, IFilter& filter, Action`1 method) bij Duplicati.Library.Main.Controller.Backup(String inputsources, IFilter filter) bij Duplicati.Server.Runner.Run(IRunnerData data, Boolean fromQueue)

Btw, when I get the error message and I press the Show button it takes me to the backup log, but this is empty because the backup fails. It took me a while to figure out there’s also a system log where you can see the actual error. :wink:


Has anyone seen this too? Might help if more people that ran into this error shared their findings.


Hello @n3wjack and welcome to the forum!

Sometimes it works best to “ask” the Internet for reports, by a web search. English version is likely:

“System.IO.IOException” “cyclic redundancy check” (adding more of the message gets fewer hits)

System.IO.IOException is a very generic higher-level mechanism which I think is passing along a lower-level error which I think is saying your hard drive is having trouble. Look at reports and judge for yourself.

I’ve searched much of the code of Duplicati, libraries it uses, and Windows system files, and it’s only in Windows kernel files (which for me are in C:\Windows\System32\en-US – yours might be in a different folder, maybe nl-NL) that I can find the string. I suspect it’s from ERROR_DATA_CHECKSUM_ERROR.

I suggest running some software (e.g. CrystalDiskInfo) that can check the S.M.A.R.T. stats of your drive.


I figured the CRC check was the backup software itself instead of the drive. The SMART info does turn up some errors with CrystalDiskInfo so that doesn’t look too good.
Thanks for pointing me into that direction.