The Hyper-V Virtual Machine Management service encountered an unexpected error: Unspecified error (0x80004005). Error code: '32768'.

 We had a request from customer to extend the RAID 10 configured disks, however there is no option to extend without deleting because of mixed RAIDs 1 and 0.

So we decided to backup the data in Veeam server and delete the existing disks RAIDs (except OS - OS not under any RAID and it has dedicated disk)  and re-configure the RAID. 

After re-configured the RAID , OS was found as it is and and Hyper-V role was remained the same (We expected the same and it will reduce couple of hours down time.) with same configurations, however other stuffs were removed. I mean (.XML, .VMCX, .VMRS, .VMGS, .VHD, .VHDX) files.

Initial issue, we found was Veeam refused to communicate with this server and got RPC failed to communicate error,

The issue, we found was routing was missing and added in the server and after that both Veeam and servers were started to talk each other.

Then, we tried to restore the VMs but got below error,

Error Restore job failed Error: Failed to create planned VM configuration (path: 'D:\VMs\<GUIDs>.vmcx'). Job failed ('Failed to import a virtual machine.
The Hyper-V Virtual Machine Management service encountered an unexpected error: Unspecified error (0x80004005).'). Error code: '32768'.

Regarding the error - it seems Hyper-V could not import the VMs and throwing error. We believe that it was due to some issue in MicroSoft file systems. We contacted the Veeam and they suggest the same or try to restore files individually and import VM manually.

We restored the configuration and disks  (.XML, .VMCX, .VMRS, .VMGS, .VHD, .VHDX) files manually and import the VMs manually and all the VMs were started to work without any issues.