136 GB of my HDD is occupied by a backup of some sort (the system information tab displays this). I use Time Machine and an external HDD for this. Any idea what this massive file is, and how to find it?
Open the Terminal in the Utilities folder and enter or paste the appropriate command line. Press RETURN and enter your admin password when prompted. It will not be echoed.
To turn them ON: sudo tmutil enablelocal
To turn them OFF: sudo tmutil disablelocal
Note that turning them OFF will also delete all existing snapshots.