Error Code 72:40 Failed to open Archive File

Article ID: MA0006 Synthetic Full backup fails with error code 72:40

Symptom

Running a synthetic full backup gives the error code:

Error Code: [72:40] 
Description: Failed to open Archive File. The connectivity between client and MediaAgent may be broken OR an invalid copy precedence may have been specified. 
Source: , Process: clRestore

Cause

Incremental backup was run on an older software version of MediaAgent before running Synthetic Full  to a MediaAgent with a newer software version. This is not supported.

Resolution

Upgrade the MediaAgent running the earlier version to the newer version.