Hyper-V Backup jobs failing with an error "The system cannot find the file specified" after upgrade to Veeam B&R 9.5 Update 4

This issue is caused by the snapshot path in the VM 's configuration being different from the actual path on a file system in terms of symbols capitalization. You can confirm this by comparing paths in bold in the Task.<VM NAME>.<VM UUID>.log file:

[22.01.2019 19:39:09] <28> Info                   [AP] (65e8) output:     <snapshots>
[22.01.2019 19:39:09] <28> Info                   [AP] (65e8) output:       <data_root type="string">C:\Temp\<VM name></data_root>
[22.01.2019 19:39:09] <28> Info                   [AP] (65e8) output:       <list>
[22.01.2019 19:39:09] <28> Info                   [AP] (65e8) output:         <size type="integer">0</size>
[22.01.2019 19:39:09] <28> Info                   [AP] (65e8) output:       </list>
[22.01.2019 19:39:09] <28> Info                   [AP] (65e8) output:     </snapshots>

[22.01.2019 19:39:09] <11> Info [AP] (65e8) command: 'file2text\n\\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy16\temp\<VM NAME>\Snapshots\<VM UUID>.xml\n2097152\n'
[22.01.2019 19:39:10] <10> Info [ReconnectableSocket] Stop confirmation was sent on [c1d84e94-b09b-4039-a8dc-4973e12934fc]. 
[22.01.2019 19:39:10] <23> Error [AP] (65e8) error: The system cannot find the file specified. 
[22.01.2019 19:39:10] <23> Error Failed to open file [\\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy16\temp\<VM NAME>\Snapshots\<VM UUID>.xml] in readonly mode.

There are two methods for correcting this issue depending on your preference:

1. Change snapshot path in VM configuration manually:

1. Connect to the Hyper-V host and go to VM Configuration of VM in question;
2. Go to Checkpoints tab and choose ‘Browse…’ underneath the snapshot path;
3. Update the path.

1. Ensure that all jobs are in a stopped state.
2. Stop all services on the Veeam Backup server that begin with Veeam. (PowerShell: gsv Veeam* | spsv )
3. Navigate to the Veeam installation folder on the Veeam Backup Server (by default it is C:\Program Files\Veeam\Backup and Replication\Backup)
4. Rename the Veeam.Backup.Core.dll file to Veeam.Backup.Core.dll_backup
5. Replace the files listed in the previous step with those found in the hotfix package
6. Start Veeam services on Veeam Backup server. (PowerShell: gsv Veeam* | sasv )