Getting error "Backup had an early error."

Uwe1 · January 18, 2026, 4:53pm

Hi everyone,

I installed UrBackup about 2 weeks ago and connected 4 Windows Client. Initial file and image backup went well for all 4 clients. Also the first incremental file backups went well.

Since a few days I mainly get above error, “Backup had an early error.”

I see this error on all clients while from time to time one backups runs thru without error.

My setup is as follows:

Server 2.5.23
installed as “community app” on “TrueNAS 25.10.1 Community Edition”
File system ZFS, no deduplication, no snapshots

Client 2.5.27
installed on Win11 25H2 or Win10 23H2

Logs will be sent by email

Would be grateful for any kind of help.

Uwe

Info	18.01.26 14:00	Starting scheduled incremental file backup…
Fehler	18.01.26 14:11	Connecting to ClientService of “Uwe” failed - CONNECT error during filelist construction (2)
Fehler	18.01.26 14:11	Backup had an early error. Deleting partial backup.

2026-01-18 14:01:06: Passive WAL checkpoint of urbackup\backup_client.db completed busy=0 checkpointed=34128 log=34128
2026-01-18 14:01:09: ClientService cmd: #Ia1FqycZ3DO84qbTuSBO9#2PING RUNNING pc_done=&eta_ms=104425&status_id=17&speed_bpms=0&total_bytes=-1&done_bytes=0&paused_fb=1#token=0CoThmVpmEs0wPNpybeI
2026-01-18 14:01:09: ERROR: Program abort (SIGABRT)
2026-01-18 14:01:09: ERROR: Fatal exception code 0 at address 0x00007FF8044EA80A
2026-01-18 14:01:10: ERROR: Fatal exception (APPLICATION CRASHED). Crash dump written to “C:\WINDOWS\TEMP\UrBackup\v2.0.0-20260118-140109-11984-3344.dmp”
2026-01-18 14:01:11: Removing deleted directories from index…

2026-01-18 12:56:42: ERROR: Error while getting files in folder “\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy3\ProgramData\Microsoft\Windows\Containers\Layers\58b1360f-962f-4682-920b-02f29e7c1d86\Files\Windows\System32\DriverStore\FileRepository\acpi.inf_amd64_6723d7de9d8549b6”. Windows errorcode: 87. Access to root directory is gone too. Shadow copy was probably deleted while indexing.
2026-01-18 12:56:42: ERROR: Indexing files failed, because of error
2026-01-18 12:56:42: ERROR: Constructing of filelist of “Uwe” failed: error - index error
2026-01-18 12:56:50: ERROR: Backup had an early error. Deleting partial backup.
2026-01-18 12:56:51: WARNING: Exponential backoff: Waiting at least 1h 20m before next file backup
2026-01-18 12:56:51: server_prepare_hash Thread finished (exit)
2026-01-18 12:56:51: server_hash Thread finished - normal

uroni · January 18, 2026, 5:28pm

Could you send this file as well. Thx!
If you have the time, might be interesting to check if this is a regression with .27 by trying to use .26: Index of /Client/2.5.26/

uroni · January 18, 2026, 7:03pm

Could also be just this: UrBackup - Frequently asked questions (if the crash was during shutdown or something?)

Uwe1 · January 19, 2026, 7:39pm

@uroni Thank you for looking into it!

Regarding FAQ:

no VSS errors
enough free space
no heavy write activity
Computer Protection is set to OFF
(must this be ON? I din’t change it and as mentioned UrBackup worked fine the first days)
max. Percentage is set to 100%
EFS is not used
I will try changing the user of the background task and test

Dump “v2.0.0-20260118-140109-11984-3344.dmp” was part of the ZIP file I sent to bugreports@urbackup.org.

Shall I send again?

Uwe1 · January 19, 2026, 7:57pm

changing the user does not help

Uwe1 · January 19, 2026, 8:45pm

set Computer Protection to ON for testing. No difference.

uroni · January 21, 2026, 9:27pm

The just released 2.5.28 should fix this issue. Thanks to everyone that reported this issue and sorry for the inconvenience.

Uwe1 · January 22, 2026, 9:30pm

I updated the client on two Computers. No big change. In Tab “Logs” I see file backups without error now. But they don’t show up in status page, I can’t see them under “Activities” and also not available under “Backup”

Uwe1 · January 24, 2026, 8:56am

did a full file backup yesterday manually. This went thru without any problem. The next incremental file backup did not work again.

Fehler	23.01.26 21:38	Error while getting files in folder “\\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy12\ProgramData\Microsoft\Windows\Containers\Layers\58b1360f-962f-4682-920b-02f29e7c1d86\Files\Windows\CbsTemp\12320_211399984”. Windows errorcode: 87. Access to root directory is gone too. Shadow copy was probably deleted while indexing.
Fehler	23.01.26 21:38	Indexing files failed, because of error
Fehler	23.01.26 21:38	Constructing of filelist of “Uwe” failed: error - index error
Fehler	23.01.26 21:38	Backup had an early error. Deleting partial backup.

Uwe1 · January 25, 2026, 3:16pm

@uroni

Shall I send new Log files?

Uwe1 · January 27, 2026, 5:18am

Any chance that we get this fixed soon?

currently I have no reliable backup. I like the concept of UrBackup very much and would like to stay. But any backup tool must be reliable.

Uwe1 · January 27, 2026, 1:23pm

Tried full file backup on three clients. All worked fine.

Incremental backup shows mentioned error on all Win11 clients. The only Win10 client I still have does not show this error.

Uwe1 · February 11, 2026, 8:35pm

still trying to get this working…..

It’s NOT an Win11 issue. One of my Win11 clients works fine now. Without any changes, never tested with this client.

It’s also NO issues with System Protection (“Computerschutz”). Doesn’t matter if this is one or off. Urbackup seams to create own VSC for backup.

Compared the two Win11 clients were one always runs into “early error”, while the other doesn’t. Couldn’t find anything significant. The Client with error has much more data and file count. The other Win11 with error is even bigger. The WIn10 and the one Win11 client without error are rather small.

Could it be, that the file list gets too big? Or that the big file list can’t be compared with the existing backup? Since only the incremental backups run into error.

@uroni any idea?

Uwe1 · February 14, 2026, 5:31pm

I did some further research and I’m quite sure that I found the reason for “Early error”.

The file list is too big!

In my last post I speculated that “size” is the only difference between clients with and without “Early error”. So I did I file count on all my clients. The two clients that get the error both have more then 1.2 Million files to back up.

When I reduce the backup scope to a single folder containing around 200.000 files I have nor errors at all.

Since full file backup always worked on all clients I assume that the routine which tries to find the modified files can’t handle so many files.

@uroni Could you please check source code if may assumption can be confirmed

uroni · February 15, 2026, 12:20pm

There is no such limit. My guess is that the error message you are seeing directly points at the cause: Shadow copy was probably deleted while indexing..

Uwe1 · February 15, 2026, 1:03pm

What probably should delete shadow copys?

And why only when backing up large number of files?

uroni · February 15, 2026, 1:06pm

Uwe1 · February 15, 2026, 3:37pm

Well, I certainly check it again. Just to be safe. But let me quote my answer from the beginning of this thread.

Uwe1 · March 3, 2026, 5:46am

sorry for delay, was on a business trip.

Tested it once again. Disk (SSD) has plenty of free space. System was completely updated (UrBackup, other apps, Windows etc.) rebooted, run in idle for about an houre. Then incremental file backup started.

Protokoll shows

Level	Zeit	Nachricht
Info
02.03.26 08:06
Starting unscheduled incremental file backup...
Info
02.03.26 08:07
Component caption=Tasks Store name=
Info
02.03.26 08:07
Component caption=Windows Managment Instrumentation name=
Info
02.03.26 08:07
Scanning for changed hard links on volume of "c:\"...
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\ActionsMcpHost.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\GameBarElevatedFT_Alias.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\GetHelp.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\MediaPlayer.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\MicrosoftWindows.DesktopStickerEditorCentennial.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\SnippingTool.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\VisualAssist.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\WindowsPackageManagerMCPServer.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\WindowsPackageManagerServer.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\WindowsSandboxRemoteSession.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\WindowsSandboxServer.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\bash.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\microsoftstore.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\ms-teams.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\ms-teams_ac.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\ms-teams_autostarter.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\ms-teamsupdate.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\mspaint.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\notepad.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\pbrush.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\python.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\python3.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\store.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\ubuntu2204.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\vhusbdwinw64.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\winget.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\wsb.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\wsl.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\wslconfig.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\wt.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\microsoft.desktopappinstaller_8wekyb3d8bbwe\WindowsPackageManagerMCPServer.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\microsoft.desktopappinstaller_8wekyb3d8bbwe\WindowsPackageManagerServer.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\microsoft.desktopappinstaller_8wekyb3d8bbwe\python.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\microsoft.desktopappinstaller_8wekyb3d8bbwe\python3.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\microsoft.desktopappinstaller_8wekyb3d8bbwe\winget.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\microsoft.paint_8wekyb3d8bbwe\mspaint.exe to read the file attributes
Info
02.03.26 08:07
Cannot open file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\users\uweet\appdata\local\microsoft\windowsapps\microsoft.paint_8wekyb3d8bbwe\pbrush.exe to read the file attributes
Fehler
02.03.26 08:07
Error while getting files in folder "\\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\ProgramData\Microsoft\Windows\Containers\Layers\609e3e7d-2ccf-4ed8-b588-ed76c7477ea7\Files\Windows\System32\DriverStore\FileRepository\mchgr.inf_amd64_d324fd60dcc3fe67". Windows errorcode: 87. Access to root directory is gone too. Shadow copy was probably deleted while indexing.
Fehler
02.03.26 08:07
Indexing files failed, because of error
Fehler
02.03.26 08:07
Constructing of filelist of "Hauptrechner" failed: error - index error
Fehler
02.03.26 08:07

Event log shows that VolumeShadowCopy28 gets provided and removed several times. Not sure if this is usual. Event log shows all VSC- and NTFS-related entries from 8:00 till 8:10, see attachment.

If your theory, that something is deleting the VSC during backup, would be right, why would happen this only during inkremental backup. Full file backup will use VSC the same way, doesn’t it? And shouldn’t we see an event deleting the shadow copy?

UrBackup3.zip (3.0 KB)

Uwe1 · March 7, 2026, 10:53pm

@uroni
anything you could add?