Failed to create a snapshot: Expected provider error. Check the event log for details

[Warning-Duplicati.Library.Main.Operation.BackupHandler-SnapshotFailed]: Failed to create a snapshot: Expected provider error. Check the event log for details

backup to my NAS which has been working for the last year or so. today? automatic job failed and so did manual/ storage is writable and available.

"2022-03-19 16:10:05 +00 - [Information-Duplicati.Library.Main.Controller-StartingOperation]: The operation Backup has started",
"2022-03-19 16:30:54 +00 - [Information-Duplicati.Library.Main.BasicResults-BackendEvent]: Backend event: List - Started:  ()",
"2022-03-19 16:31:01 +00 - [Information-Duplicati.Library.Main.BasicResults-BackendEvent]: Backend event: List - Completed:  (486 bytes)",
"2022-03-19 16:31:02 +00 - [Information-Duplicati.Library.Main.BasicResults-BackendEvent]: Backend event: List - Started:  ()",
"2022-03-19 16:31:03 +00 - [Information-Duplicati.Library.Main.BasicResults-BackendEvent]: Backend event: List - Completed:  (486 bytes)",
"2022-03-19 16:31:03 +00 - [Information-Duplicati.Library.Main.Operation.FilelistProcessor-KeepIncompleteFile]: keeping protected incomplete remote file listed as Temporary: duplicati-20220319T161005Z.dlist.zip.aes"

],
“Warnings”: [
"2022-03-19 16:30:06 +00 - [Warning-Duplicati.Library.Main.Operation.BackupHandler-SnapshotFailed]: Failed to create a snapshot: Expected provider error. Check the event log for details

is all i’m getting in the full log. windows 10 pro to SMB share. other jobs to the same storage worked fine today.

Are other jobs from this same drive on this same computer at about this job’s time?

snapshot-policy affects what is done before the backup in terms of a VSS snapshot.
Yours seems to be set to required maybe because it’s critical to have a snapshot?

Sorry about the poor error message, but it looks like that’s all that Duplicati was told.
If you’re backing up from a drive (not a database) the Provider is probably Windows.

C:\>vssadmin list providers
vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool
(C) Copyright 2001-2013 Microsoft Corp.

Provider name: 'Microsoft Software Shadow Copy provider 1.0'
   Provider type: System
   Provider Id: {b5946137-7b9f-4925-af80-51abd60b20d5}
   Version: 1.0.0.7


C:\>vssadmin list shadowstorage
vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool
(C) Copyright 2001-2013 Microsoft Corp.

Shadow Copy Storage association
   For volume: (C:)\\?\Volume{bbb9f1b2-0000-0000-0000-300300000000}\
   Shadow Copy Storage volume: (C:)\\?\Volume{bbb9f1b2-0000-0000-0000-300300000000}\
   Used Shadow Copy Storage space: 0 bytes (0%)
   Allocated Shadow Copy Storage space: 0 bytes (0%)
   Maximum Shadow Copy Storage space: 93.1 GB (10%)


C:\>

The 10% just above is because I raised mine. I don’t know if your space may be full.
Settings → System → About → Advanced system settings → System Protection
or vssadmin resize shadowstorage can give you more space (if that’s the issue).

VSS: Backup fails with “Expected provider error. Check the event log for details.” (119509)

was the top (and one of the more specific) results from a Google search for the error.
That says a little more on what was in that event log, plus a note about too much I/O.
Does the error come and go? Does it occur if backup runs when system is not busy?

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hi and thanks for taking the time to post such an informative reply.
apologies for the delay in getting back to you. not sure how to split things into sections so…

i use VSS for Outlook and a couple of other pieces of software (DBs) that are always running when this backup job kicks in. there aren’t any other jobs scheduled on this machine closer than 60 minutes in start time.

this particular job is backing up from a win10 pro machine

PS C:\WINDOWS\system32> vssadmin list providers
vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool
(C) Copyright 2001-2013 Microsoft Corp.

Provider name: 'Microsoft Software Shadow Copy provider 1.0'
   Provider type: System
   Provider Id: {b5946137-7b9f-4925-af80-51abd60b20d5}
   Version: 1.0.0.7

PS C:\> vssadmin list shadowstorage
vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool
(C) Copyright 2001-2013 Microsoft Corp.

Shadow Copy Storage association
   For volume: (C:)\\?\Volume{a1e4c1ed-f5e5-49a9-a5ee-04b68ef475fe}\
   Shadow Copy Storage volume: (C:)\\?\Volume{a1e4c1ed-f5e5-49a9-a5ee-04b68ef475fe}\
   Used Shadow Copy Storage space: 0 bytes (0%)
   Allocated Shadow Copy Storage space: 0 bytes (0%)
   Maximum Shadow Copy Storage space: 2.36 GB (2%)

and this is going to a NAS with RAID5 which currently has 786GB free. it’s a 2.06GB backup at the source end and currently there’s 5.08GB of backup data stored with 171 versions. interesting shadow commands thanks. hadn’t come across those before. i could look into raising the storage that’s allowed for it.

the backup hasn’t thrown this error since. I fear i have messed up the formatting along the way with this one and i hope it still makes sense.

I think mine was also at 0% for awhile, so I’m not sure how VSS worked, but it “usually” did.

Failed: Failed to create a snapshot: The creation of a shadow copy is already in progress.
Details: Duplicati.Library.Interface.UserInformationException: Failed to create a snapshot: The creation of a shadow copy is already in progress. ---> Alphaleonis.Win32.Vss.VssSnapshotSetInProgressException: The creation of a shadow copy is already in progress.
   at Alphaleonis.Win32.Vss.VssBackupComponents.StartSnapshotSet()
   at Duplicati.Library.Common.IO.VssBackupComponents.InitShadowVolumes(IEnumerable`1 sources)

is my most common VSS failure, but it’s rare enough that I can’t figure out what’s interfering.

I did try raising VSS storage space anyway using the GUI method I described. Didn’t stop it.
My inspiration for trying might have been the below message (or maybe it was another one).

Failed: Failed to create a snapshot: The system was unable to flush I/O writes. This can be a transient problem. It is recommended to wait ten minutes and try again, up to three times.
Details: Duplicati.Library.Interface.UserInformationException: Failed to create a snapshot: The system was unable to flush I/O writes. This can be a transient problem. It is recommended to wait ten minutes and try again, up to three times. ---> Alphaleonis.Win32.Vss.VssFlushWritesTimeoutException: The system was unable to flush I/O writes. This can be a transient problem. It is recommended to wait ten minutes and try again, up to three times.
   at Alphaleonis.Win32.Vss.WaitCheckAndReleaseVssAsyncOperation(IVssAsync* pAsync)
   at Alphaleonis.Win32.Vss.VssBackupComponents.DoSnapshotSet()
   at Duplicati.Library.Common.IO.VssBackupComponents.InitShadowVolumes(IEnumerable`1 sources)

Overview of Processing a Backup Under VSS is what happens, except sometimes it doesn’t.

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thanks for the detailed, and further, info.
been swamped and have only just gotten around to replying so apologies for that.
the backup job has continued to run without incident so i have left settings as they are for the moment.
bookmarked this thread however so i can refer to your findings should i need to try and alter anything should the issue happen again.
appreciate all your input.

1 Like