1) Quit Google Drive File Stream
2) Delete Google Drive File Stream.app from the application folder
3) Delete folder /Library/Application Support/Google/DriveFS
4) Delete files /Library/Preferences/com. google.drivefs.plist (and anything else from com.google.drivefs)
5) Empty trash
6) Re-start
7) Reinstall from https://dl.google.com/drive-file-stream/googledrivefilestream.dmg