Challenge
File level restore fails, or displays fewer disks than expected.
Cause
Windows File Level Restore is limited to displaying 20 virtual disks. Multi-OS File Level Restore is limited to browsing VMs with 16 virtual disks.
Solution
You can use VM Hard Disk Restore or VM Files restore to restore only those disks that contain data needing to be restored, and attach those disks to a VM in order to retrieve files. You can also use Instant Recovery to restore the entire VM.
Key: HKLM\SOFTWARE\Veeam\Veeam Backup and Replication\
DWORD: VdkMaxDisksNum
Default value: 20 (decimal)
Max Value: 128
Set the value to a number greater than the largest number of disks on any of the VMs in your environment.
Please keep in mind that attempting to perform an FLR with from a VM with a large amount of disks may take a very long time.