When opening the Symantec Endpoint Protection (SEP) GUI through the tray icon, the interface doesn't open. Instead one or more error messages may come up:
* Error - SymCorpUIRes.dll could not be found.
* Symantec Endpoint Protection - Error: The resource file version does not match the version of the file trying to load it - cannot load ProtectionUtilRes.dll
Release : 14.3 RU4
Two SEP versions may be installed at the same time causing conflict/ errors. Check Programs & Features to see if this is the case.
Both versions should be removed, either manually or using the Cleanwipe tool.
Afterwards, reinstall the latest version.