Backups are failing because of OSearch<xx> VSS writer (4041637)

Specific agent machine cannot take backups, getting VSS error. Examination of the agent's Event Viewer indicates that OSearch<xx> VSS writer is a culprit.
<xx> is the Sharepoint version, could be Osearch14, Osearch15, Osearch16

Error on the Core: "The VSS writer 'OSearch15 VSS Writer' failed during the 'DoSnapshotSet' phase with error WriterErrorNonRetryable."

For the immediate workaround, please do the following on the Core server:

- click on the agent's name
- click on Settings in the right pane
- scroll down to the list of excluded VSS Writers
- click on OSearch<xx> writer, word "No". Change it to Yes and click on checkmark to finalize the change
- force an agent snapshot to verify that backup is now taken successfully

For more in-depth troubleshooting, without excluding Osearch VSS writer, please do the following on the protected agent:
- open Event Viewer, Application and look for EventID 8193

- got to event Details, scroll down to the Binary section and look in the Binary to Word part to verify which account name was used:

- open regedit and Navigate to HKLM > System > Current Control Set > Services > VSS
- right-click VSS key, select Permissions and add that account to the list with Full Control rights