Symantec Protection Engine (SPE) functions fail to work as expected at times when local Antivirus is installed.
Local antivirus (such as SEP) can sometimes interfere with essential files and folders within the installation directory. These interferences can cause the following:
Configure your Antivirus software to exclude SPE's installation directory listed below. If you have installed SPE into a directory other than default, replace these paths with the ones you used:
C:\Program Files\Symantec\Scan Engine\