Erasing free disk space

Joined
Jan 7, 2009
Messages
8
Reaction score
0
Points
1
When I tried to do this my free memory went to near zero, I currently have 29Gb free, I stopped it because I was confused. What does erasing free space do? Can I still use the space? Or does it make it unusable?
 
OP
B
Joined
Jan 7, 2009
Messages
8
Reaction score
0
Points
1
No it really doesn't.. It doesn't really answer my questions :l

So at the end of the erasing the space I will have no free space at all? Thats crap..
 

bobtomay

,
Retired Staff
Joined
Dec 22, 2006
Messages
26,561
Reaction score
677
Points
113
Location
Texas, where else?
Your Mac's Specs
15" MBP '06 2.33 C2D 4GB 10.7; 13" MBA '14 1.8 i7 8GB 10.11; 21" iMac '13 2.9 i5 8GB 10.11; 6S
Yes, it really does.

There is no reason the average user would ever need to erase free space. Since you're not familiar with what it does, am pretty sure you don't need to do this.

Both Windows and OS X, when you delete a file, the file is not actually deleted, only the pointer that tells the operating system where the file is located. The 'deleted' file is still there on your hard drive until such time as it is overwritten by new data and would be recoverable by most any data recovery software.

Erasing free space writes 0's to the drive, essentially overwriting whatever data was 'deleted', in order to make it un-recoverable.

If you do have a 'need' to do this, you must realize that it is writing 0's to all of the free sapce on the entire drive and should only be done while you are not using the machine. With a large drive, it could take a while to write 0's to the entire disk. Once the process has finished, all the free space will be returned to it's previous free space status.
 

Shop Amazon


Shop for your Apple, Mac, iPhone and other computer products on Amazon.
We are a participant in the Amazon Services LLC Associates Program, an affiliate program designed to provide a means for us to earn fees by linking to Amazon and affiliated sites.
Top