Backups failing - freeze/thaw VSS failures or broken Agent when CarbonBlack, SentinelOne, Sophos, Trend Micro are used

Security software known for either damaging
Unitrends Backup; Recovery Series; Unitrends Free; Unitrends Agents
RS/UB 10.3; RS/UB 10.2; RS/UB 10.1; RS/UB 10.0; RS/UB 9.2
Backups fail citing VSS freeze/thaw events and customer is utilizing Sophos AV.

GetWriterStatus: USNAPError! GatherWriterStatus call has returned a failure.
(VSS_E_WRITERERROR_TIMEOUT) The writer's timeout expired between the Freeze and Thaw events.
Please check Windows Events Log that Volume Shadow Copy Service and VSS Writers are operating properly.

To confirm, leverage the command:
# fltmc instances
Please see the following KB written specifically to address this ongoing issue:

Please direct any implementation related questions to this Sophos provided workaround to Sophos technical support.

In addition to the above Sophos fix also confirm that the exceptions listed in this KB 5800 are applied for your antivirus programs
Sophos Health Service may have unexpected impacts to the success of guest-level backups.
For details on the 'fltmc instances' command see
Josh Gabel
Luis Perez

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