LiveUpdate status shows Rapid Release definitions failing every few seconds.
When viewing ...Program files\Symantec\Symantec Endpoint Protection Manager\tomcat\logs\Sesmlu.log, the following entry appears:
ERROR SesmLu: DU_E_MISSING_CATALOG_FILE at .\SesmLu.cpp
A Rapid Release file (.jdb) has been placed into the C:\Program Files \Symantec\Symantec Endpoint Protection Manager\data\inbox\content\incoming folder to update the antivirus definitions. The .jdb file was not successfully deleted after it was processed, so the Symantec Endpoint Protection Manager was constantly trying to install it.
Navigate to C:\Program Files \Symantec\Symantec Endpoint Protection Manager\data\inbox\content\incoming and delete the contents of the incoming folder.