Problems on Win Server 2012 Failed to process path: * => I/O error occurred

Hi Forum,

I found a view things, but not all. I found an other topic but there the problem is not solved. (Cannot backup files on a windows server · Issue #1202 · duplicati/duplicati · GitHub)

I have Duplicati on an Win Server 2012, set up with Storage Spaces.

I ran duplicati service as “Local System account” and also as admin user…

I already installed the Visual C++ 2015 redist package installiert werden:

Some files are backuped but very much files make this error:

Failed to process path: S:\scan\E-Mail 13 G-T00-1.jpg
Alphaleonis.Win32.Filesystem.UnrecognizedReparsePointException: I/O error occurred.

   at Alphaleonis.Win32.Filesystem.Device.GetLinkTargetInfoCore(SafeFileHandle safeHandle)

   at Alphaleonis.Win32.Filesystem.File.GetLinkTargetInfoCore(KernelTransaction transaction, String path, PathFormat pathFormat)

   at Duplicati.Library.Snapshots.WindowsSnapshot.GetSymlinkTarget(String file)

   at Duplicati.Library.Main.Operation.BackupHandler.HandleFilesystemEntry(ISnapshotService snapshot, BackendManager backend, String path, FileAttributes attributes)

this is from the server log (solved):

Volume Shadow Copy Service error: Unexpected error querying for the IVssWriterCallback interface.  hr = 0x80070005, Access is denied.
. This is often caused by incorrect security settings in either the writer or requestor process.

The Serverlog info is solved with this hint:

May someone help me?
Thank you!

Welcome to the forum, and thanks for trying out Duplicati!

It sounds like you already did some good research on your issue - does that mean you already saw these these topics and they didn’t help?

Hello, thank you for the friendly welcome!

Yes, i saw this two topics.

For testing i tryed to backup data from an external drive on the server.
No error was showen, worked fine.

The problem only exists if I backup from an Drive where “Data dedublication” is on.

Is there a workaround for this, otherwise I would have to turn off this Feature.

I have an second question about the encryption:
Is it more secure to use GNU Privacy methode?

I cannot find any howto for this method…

Thank you for your help!

Unfortunately, I don’t have any experience with either of those items so don’t know that I can help much. :frowning:

Unfortunately, neither do I. But I found this articles on having both VSS and Dedup activated:

It mentions some issues, unfortunately not specific to your experience, but maybe something helps you understand the problem better.

That depends on who you trust. Robustness-wise I would recommend only using the AES encryption module, as that is built-in, and has a good track record.

GPG on the other hand, is much older (good for trust) but also difficult to use. The integration in Duplicati works by calling the gpg.exe executable, which is a potential security issue itself (i.e. an attacker installs a proxy gpg.exe that also logs the keys). But it also offers all the features that GPG has (various encryption methods, key strengths, etc).

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I thank you both very much for your help!

My workaround is to make a robocopy to an external disc and after this duplicati runs from there.

Thank you for the encryption hints, now I use the integrated mode. (And in general I trust nobody ;))

All the best!

I found a few interesting articles:

  • There are similar issues with .NET based backup software that use AlphaVSS for creating snapshots:
  • I read that storing data and diffs on the same drive can cause problems. Did you try to move the location for shadow copies to a different, dedicated drive? You can check the location of your shadow copies by running vssadmin list shadowstorage from an elevated command prompt. Moving the shadow copy location to another volume is described here.