Windows Server 2016 Hyper-V Guests Backup failed Event Id 517 Error 0x807800C5 0x8078004F



since an update installation at the 29th May (KB5001402, KB5003197 & KB890830) our backup of the Hyper-V guests doesn´t work anymore.

Windows Server 2016 Standard 1607 build 14393.4402 - Hyper-V role (with GUI)

The backup started the VSS and after seconds the VSS crashed with the event id 517 0x807800C5.

After restart the behavior is the same, but with error 0x8078004F (instead of 0x807800C5).


Fehlerbucket , Typ 0
Ereignisname: Windows Server Backup Error
Antwort: Nicht verfügbar
CAB-Datei-ID: 0

P1: 4
P2: 1
P3: 0x8078004f
P4: 0x8078001d
P5: 0x00000000
P6: 0x00000000
P7: 0x00000000
P8: 0x8078001d


We tried several local backups, failed wit the same message.

We checked the VSS environment without any results. Did it with Acronis VSS tool, too - no results.

Switched off the security software didn´t change anything.


I appreciate your help.



Stefan Schoen



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