Getting error "Backup had an early error."

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

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/

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