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Level 1

6 points

Massive unknown backup

Hi all,

I was trying to get rid of unwanted files and clean my HDD and external HDD when I noticed my external HDD had a massive amount of backup data on it. Of the 2TB available, 900GB is taken by this 'backup'. I don't know what it is or where it came from since I haven't created a backup for over a year.

I found this http://support.apple.com/kb/HT4878?viewlocale=en_US could be the problem. I wanted to ask before I proceed though. When I use these commands in Terminal it tells me it might lead to data loss or deletion of important system files. Is this really a safe method? If so, do I have to turn it back on again afterwards? Will my Macbook suffer if I don't turn it back on?

I hope someone can help me on this case. Sorry if there are numerous discussions about this topic already, but I didn't know what to put in search to find a match.

MacBook Air, OS X Mavericks (10.9.3)

Posted on Jun 2, 2014 6:29 PM

18 replies

Linc Davis

Level 10

209,547 points

Jun 3, 2014 7:41 AM in response to diverqent

Disconnect the external drive and put it in a drawer. Connect another external drive. Set it up with Time Machine.

After some time to be decided by you, such as a week or a month, you will decide that the data on the old drive is no longer going to be needed for restoring. At that point, you can reconnect the drive and erase it. Set it up again with Time Machine. It may now work, or it may not. If not, erase it again and take it to a recycling center.

diverqent Author

Level 1

6 points

Jun 4, 2014 7:12 AM in response to Linc Davis

I also just discovered something else. I've been downloading some movies lately and their sizes ranges from 4 to 10GB. The thing is, I've got only 10 of them. When I click 'show info' it tells me the map is 580GB. This is not possible. There's aslo another map containing music videos not even 100MB large and it tells me that map is 300GB. Could it have to do something with these videos?

diverqent Author

Level 1

6 points

Jun 4, 2014 8:08 PM in response to diverqent

Nevermind. I found the cause of the problem. First of: I scanned my external HDD again and it showed no errors this time. Is this usual the second time? Second: these 'backups' are actually my movies. I tried renaming them .mp4 instead of .mkv/etc. and the exact size of the movie got extracted from the backup part, but got added to the movie category. It seems the mac does not recognise these extensions. Is there a way to solve this?

Massive unknown backup