Summary
Backup fails on Windows nodes when multiple devices have the same unique ID.
Symptoms
The backup fails and a job log message similar to the following is displayed:
SNBAPH_126E Func(backup_): Exception (the unique-id ({4C8C920F}) is used 4 times by sssnap in BACKUP response.
The ID 4C8C920F represents the hardware device ID found. If there is more than one instance of a hardware device found, the job log reports the number of instances found. Four instances are found in the above example.
The error does not typically occur on Windows servers, however the error can be encountered if a Windows server IA maps one or more devices, resulting in duplicate physical device numbers.
Resolution
In the case of multiple IA maps, simply detach the maps.
If this issue exists on a Windows server where IA map is not used, you may need to contact Microsoft technical support for assistance in correcting the issue. If you have another device available, it may be easier to copy your data to an alternate device and decommission the conflicting device.
The cross referenced KB article below indicates possible additional conditions and corrective steps.