I just backed up my 1TB (mostly full) internal hard drive to an external 1TB Time Machine drive, and it says I'm fully backed up. Why is the Time Machine drive only half full?

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I just backed up my 1TB (mostly full) internal hard drive to an external 1TB Time Machine drive, and it says I'm fully backed up. Why is the Time Machine drive only half full?

I have a 1TB internal drive in my MacBook Pro (15", mid-2009, running Snow Leopard). A couple days ago I decided to format my unused 1TB external drive and use it for Time Machine, so I could wipe/format my internal drive for the Mavericks upgrade I've been putting off. Time Machine backed up the entire drive, and it appears to have successfully worked! Except that Finder shows 157 gigs free on my internal drive and 463 gigs free on the external... I'm hesitant to erase everything in case some stuff didn't get backed up and might disappear. A Google search tells me that Time Machine doesn't compress files at all... so where the heck did those 300 gigs go? Is there really 300 gigs of stuff on my internal drive that Time Machine just decided didn't need to be backed up?

MacBook Pro (15-inch Mid 2009), Mac OS X (10.6.8)

Posted on Mar 17, 2014 5:22 PM

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Answer 1

Best reply

Eric Ross

Level 6

11,807 points

Mar 17, 2014 5:37 PM in response to Bunda the Great

By default Time Machine will not back up all files, i.e. temp file, cache, and system files. Also you can set Time Machine to exclude some folders/files, take a look at this link for more information. http://pondini.org/TM/11.html

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Answer 2

Mar 17, 2014 7:58 PM in response to Eric Ross

But is 300+ gigabytes a normal amount of temp/cache/system files to exclude? I would expect maybe ten to fifty gigabytes, but three hundred? Is there an easy way to clear those off of my main internal hard drive without doing a full wipe?

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