Space used

[DanL]

I believe this is a regularly asked question, so pardon my naivite, but I am struck by the fact that Get Info reports that my disk volume has 110GB "Used", but the Finder lists only 96GB worth of stuff in it. What's the 14GB? That's a lot of stuff that the Finder doesn't seem to be aware of. FWIW, my SuperDuper backup volume seems to have 99GB "Used", so a lot of that 14GB is evidently not very important.

 

[Lufbrarunner]

There may be some 'purgeable' space on the drive, also files can take up more space than their file size would suggest, due to how the disk is formatted.

 

[DanL]

Well, different apps seem to define "space used" differently. I can't see any reason for such inconsistency.

 

[Cory Cooper]

Hello,

There are some "hidden" System files that aren't always part of the reported total, and some is related to how the drive is formatted as Lufbrarunner mentioned.

C

 

[DanL]

Well, as I said, my backup suggests that a lot of those "hidden" System files aren't very important. Just a little disconcerting that you can't seem to get a straight answer to the question - how much space am I using? To the extent that space is "purgeable", why doesn't the OS just purge it?

 

[Lufbrarunner]

........... why doesn't the OS just purge it?

It does, if the space is needed it will be overwritten.

 

[DanL]

Ha ha. Well, OK, so there is no straight answer to the question - how much space am I using. If I want to back up to a 125GB partition, just because it says somewhere that I only have 100GB, doesn't mean that I can do it. In fact, I was prevented from doing exactly that, because had a large amount in the Trash, but if I had 14GB more space, it could have done it. But it didn't.

So I guess that purgeable space can be overwritten if you need to save more, but if you need to be using less space, no joy.

 

[Lufbrarunner]

Clear purgeable space link. I have not tried this myself but it seems that some people have had success with it.

 

[DanL]

Thanks. That's interesting. Since when does Get Info offer up a count of "purgeable" space in the "Available" column? Never seen that. That would be useful to know, because it would tell you what you stand to gain by cleaning things up.

 

[DanL]

OK, I believe I'm learning that Mac OS only started telling you about purgeable space with Sierra.

 

[Lufbrarunner]

That sounds about right, my El Capitan machine does not report this info.