You find that when your Symantec Endpoint Protection (SEP) client computer experiences poor performance, the Sesclu.exe process appears to be using a large amount of the CPU.
Poor system performance with the Sesclu.exe process using a large amount of the CPU
This issue can be the result of damaged virus definitions.
To resolve this issue, you can remediate virus definitions on the SEP client.
Refer to the How to clear out corrupted definitions for a Symantec Endpoint Protection Client document for detailed instructions.