"System" Using Ridiculous Amount of Space (750GB)

[penajmz]

How can I find what this is?

750GB that I have no idea what it is. It's driving me crazy right now.

I found some files that were mysteriously duplicated by themselves..... Don't ask how because i have no idea. The this:

 

[FNH15]

Boot into recovery and verify your disk. Then, check your user library and see if anything there is taking up an inordinate amount of space.

 

[mark-vdw]

There's a few good tools out there that analyze disk space usage, like Disk Inventory X. They'll give you a better breakdown compared to what "About this Mac" offers.

One thought: I seem to remember that files in the Trash are counted under "System".

Taking it from another angle: There's not many file types that will fill up 750GB. Movie collections or massive photo libraries are the first that come to mind. If those are in an unusual location, the system may be counting them in the wrong category. Are you sure those are accounted for?

 

[h9826790]

Sometime boot to safe mode and boot back to normal desktop can fix it (or part of it), because boot to safe mode will allow the system to remove all useless cache files, which may be >100GB after some time.

 

[cynics]

For some reason the new 'about this mac' indicates my movies as system which is ~700gb.

Is there a chance you are using that much space but it's just not being reported correctly?

 

[Feenician]

The advice above about checking disk health and using a 3rd party application like DiskInventoryX (or my favorite free one, OmniDiskSweeper) is good and you should do that op. Once you've done those it's worth rebuilding spotlight for the disk too (add it then remove it from Spotlight privacy) as those classifiers are built from spotlight info and may simply be corrupt and misclassified.

 

[penajmz]

Thanks guys, went and got DiskInventoryX and found out it was Xcode simulators taking all that space.