To get rid of Microsoft AutoUpdate on Mac, remove these files and folders:

In the System Library (you need "sudo"):

• Folder: /Library/Application Support/Microsoft/MAU2.0
• File: /Library/LaunchDaemons/com.microsoft.autoupdate.helper.plist
• File: /Library/LaunchAgents/com.microsoft.update.agent.plist
• File: /Library/PrivilegedHelperTools/com.microsoft.autoupdate.helper

In your user's Library (needs to be done for each user):

• File: ~/Library/Preferences/com.microsoft.autoupdate2.plist
• File: ~/Library/Preferences/com.microsoft.autoupdate.fba.plist
• Folder: ~/Library/Application Support/Microsoft AU Daemon
• Folder: ~/Library/Application Support/Microsoft Update Assistant
• File: ~/Library/Saved Application State/com.microsoft.autoupdate2.savedState

Depending on the version (2011 or 2016/O365), you may miss one or more of these files and folders.