Free/Used hard drive space weirdness?

So I don't know whats going on with my MacBook Pro. I'm running OS X 10.7.1.

It all started with iStat Menus. I had hard drive usage turned on and my free space is listed around 237 GB.

I checked the Finder (after turning the status bar back on) and it lists 306 GB free.

I went into About This Mac and clicked storage, and it's reporting 253 GB free.

Ummm.... what? I'm a bit confused. Anyone had this happen to them? I get iStat Menus being wrong because it is a third party program. But Finder/About both being different (and such a wide range different!)?

Any ideas?

paulsalter said:

the difference between iStat menus and the mac could be the way disk space is calculated (SL/Lion use base 10, most things use base 2)

in the about this Mac section, does it show an amount under backup, this could be the differences as I believe this is only temp used while the mac has the space

Click to expand...

Thank you. It does appear that there is a backup calculated in About my Mac which, when left out, makes it balance out when subtracted from my total space and it matches what Finder says.

I found an option to turn on Base 10 in iStat and it now matches About my Mac.

Didn't know about backups.

THANK YOU!