Hi,
This is a tricky one check this
There are one or more system or user-based scans in the registry that have a missing or invalid status. This is usually the result of a migration from Symantec AntiVirus to Symanted Endpoint Protection. User-based scans are stored in the following location under the user's profile: HKEY_CURRENT_USER\Software\Symantec\Symantec Endpoint Protection\AV\Custom Tasks\ System scans are in the following location: HKEY_LOCAL_MACHINE\Software\Symantec\Symantec Endpoint Protection\AV\Custom Tasks\ These registry keys usually contains one or more tasks. The task ID is random, for example: HKEY_CURRENT_USER\Software\Symantec\Symantec Endpoint Protection\AV\Custom Tasks\C9FD1449-694F-40F1-99E5-1976D4279E0D
Try this
Delete any custom task that does not have a corresponding entry in the SEP interface, and rescheduled if neccesary