"This update is restricted" error when upgrading my system to High Sierra I uninstalled Symantec from my work computer about a year ago but now that I am trying to upgrade it to High Sierra, I get this blocker:  



How do I get rid of this?
This message is not part of macOS, but rather is part of a 3rd party MDM (Mobile Device Management) solution that your administrator has installed on your computer. You should contact your administrator.