Disable MobileBackups in Mac to Save Space.
🗓I noticed a while ago that the size of my drive was constantly getting less and less, and I never understood why. Between using Google Docs and Google Music I really don't have that much information actually stored on my Macbook--which is why I purchased a small 120GB SSD thinking that 120GB would be more than enough. It was for a while, but I started to notice less and less space being available despite not really installing anything new. I was eventually able to track this down to a new Time Machine feature in called MobileBackups. MobileBackups essentially is like Time Machine without the external drive. Whenever you disconnect your Macbook from  your Time Machine drive Lion continues to backup your drive in a safe location called "MobileBackups". You can't access it from your Finder Window and there is really no clear cut way to disable this in your settings. Literally there is no option for it. As far as I know Apple didn't really even talk about this feature when they released OS X 10.7.
To disable it all you need to do is fire up Terminal, which you can most easily access by going to Spotlight and typing in Terminal.
Enter the following line in and hit enter:
sudo tmutil disablelocal
You'll be asked for your Password simply provide it and hit enter when ready. Note -- You won't see yourself typing the password, this is a security feature and is normal.
Once you've done that you are all set! You might hear your fans whirl up for a little bit as Mac OS X is deleting all your useless MobileBackups, but other than that you are home free.
Enjoy all the space you've recovered!
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