Hidden local backups with Mac OS X Lion filling up your MacBook hard disk!

- You have a MacBook or MacBook Air running Mac OS X Lion?

- Ever wondered why you are loosing GB worth of hard disk space every day? 

- Using Time Machine?

Apple considered to implement a new “feature” to Lion that no one seems to be aware of: Local Backups if your Time Machine Drive is not connected to you computer. It seems to affect only Mac Laptops, not the desktop Macs. So every time your Time Machine backup starts without the destination drive it will copy all data in a secure folder on your local startup volume called “.MobileBackups”. If you go to “About this Mac” and “More information”, check the “hard disk” tab. You will find some information on how many GB are used for “Backup”. In my case there were 35GB stored on my local drive. Without me even noticing.

It’s great if you are travelling and accidentally deleted a document. But thsi feature takes up a lot of storage. Mayby it would be easier to wait and use the Time Machine Backup back at home?

Don’t worry, you can still disable this “feature”:

Open up the Terminal App and type

sudo tmutil disablelocal

It will take a while for the system to delete the folder. It is renamed instantly to “.MobileBackups.trash” and consequently deleted. You will notice a slower Mac and the fans could start up. But after a few minutes everything should be back to normal.