Hi,
please share the output of pveversion --verbose from the Proxmox VE host and proxmox-backup-manager version --verbose from the PBS host.
Also, please share the VM config obtained by running qm config <VMID> for the VM in question and share the output of /var/log/proxmox-backup/file-restore/qemu.log.
Did you try to restore from the same VM/snapshot two weeks ago? Any updates in-between? Further, if the file restore log folder still contains the log file from 2 weeks ago, please do also share that one, you should be able to locate it via ls -la /var/log/proxmox-backup/file-restore/
Thanks for the logs (please do however use text in code tags over screenshots for better readability).
So far it seems that the filesystem is simply not mountable via ntfs3.
May I ask the following to narrow down what might be the cause for that:
Was there any changes inside the Windows VM, especially regarding filesystem e.g. enabled bitlocker, deduplication, ...
Can you still access the snapshot you tested with 2 weeks ago (the one you showed above is from last Friday according to the timestamp, so more recent).
Are you able to map the snapshot to a loop device and then mount the disk by proxmox-backup-client map vm/100/2025-01-31T20:00:02Z drive-scsi0.img and then mount -t ntfs3 /dev/loop0p3 <mountpoint>, with a given mountpoint and adaption to the loop device name if the number is not the same.
Check and post also the output of dmesg if the mount fails.
Windows Updates are installed automatically, no Bitlocker, cannot access the old snapshot i tested two week ago. The other things I will test later. I have Synology Active Backup Agent running on this VM, could this be the problem?