Sometimes, it is noted that if there are corrupt virus definitions downloaded by SEPM, it is required to clean them up and download the virus definitions again.

Following are the steps for the same:

File system cleanup for 32-bit SESC Virus Definitions:

1. Stop SEPM server service.

2. Go to C:\program files\symantec\symantec endpoint protection manager\Inetpub\content\{C60DC234-65F9-4674-94AE-62158EFCA433}" folder and move all of the subfolders to another place, such as C:\Temp if you want a backup, otherwise delete the sub-folders.

Database cleanup for 32-bit SESC Virus Definitions:

3) Go to C:\Program Files\Common Files\Symantec Shared\SymcData\ and delete the following folders:
sesmipsdef32
sesmipsdef64
sesmvirdef32
sesmvirdef64

4)In the registry, navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Symantec\InstalledApps.
Delete these keys
SymcData-sesmipsdef32
SymcData-sesmipsdef64
SymcData-sesmvirdef32
SymcData-sesmvirdef64

5). In the registry, navigate to and delete the following keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Symantec\SharedDefs\SymcData-sesmipsdef32
HKEY_LOCAL_MACHINE\SOFTWARE\Symantec\SharedDefs\SymcData-sesmipsdef64
HKEY_LOCAL_MACHINE\SOFTWARE\Symantec\SharedDefs\SymcData-sesmvirdef32
HKEY_LOCAL_MACHINE\SOFTWARE\Symantec\SharedDefs\SymcData-sesmvirdef64

6). Start the SEPM service back up.

7). Run Live update from within the Symantec Endpoint Protection Management console.

This will re-populate the database which in turn will update the moniker folders.