Endpoint Protection (SEP) installer or other Symantec tools may fail to run on macOS 10.12 "Sierra" or newer, with various errors.
Possible errors all with same general cause:
This may be caused by a macOS security feature that assigns extended attributes ("com.apple.quarantine") to any file that has been downloaded from a network site or has been moved from its original download location ("App Translocation"). Other circumstances also may have altered macOS file attributes or permissions settings.
Symantec Endpoint Protection
macOS 10.12 "Sierra" or newer