qemu-img: Could not apply snapshot 'tt': Device has active dirty bitmaps
This happens on all our proxmox vms which are backuped with veeam.
Doesn't matter if startet or not, and if the snapshot was before or after the backup
The machine gets locked. qm unlock "vmid" and it starts at the last state.
That sounds like a technical issue. Please provide a support case ID for this issue, as requested when you click New Topic.
Also, remember that support can assist you better if you upload logs, as mentioned here.
Rovshan Pashayev
Analyst
Veeam Agent for Linux, Mac, AIX & Solaris