After installing Symantec Endpoint Protection (SEP) 14.3 on Windows 10 clients the regsvr32.exe process hangs.
Application Control
Symantec Endpoint Protection 14.3
Windows 10 1903 and 1909
This issue is fixed in Symantec Endpoint Protection 14.3 MP1. For information on how to obtain the latest build of Symantec Endpoint Protection, see Download the latest version of Symantec software here.
Workaround
Set an Application Control exception for C:\Windows\System32\regsvr32.exe.
https://knowledge.broadcom.com/external/article/181736/how-to-create-an-application-control-exc.html
ESCRT-4096