Persistence of Symantec Endpoint Protection's (SEP's) clean file cache may cause hang on shutdown or restart.
There is a potential race condition between SEP's Auto-Protect and the clean file cache that may cause a hang when shutting down or restarting a computer.
This issue has been fixed in SEP 14.0.1 (RU1) through Auto-Protect driver update 15.0.25. For information on how to obtain the latest build of Symantec Endpoint Protection, see Download the latest version of Symantec Endpoint Protection.
Related: How does the "Rescan the cache when new definitions load" feature work in SEP?