Welcome to the MacNN Forums.

jeff k · May 26, 2015, 01:46 AM

I went to do an OS update and it says I need 7gb and I don't have that.

So I looked at the Mac HD.

Users says I'm taking up 12GB, but I open that folder and I see only about 3GB of stuff in there.

Apps says it taking up 10GB, and I look in that folder and see about 3-4 GB of apps in there.

Library says it's at 8gb, and I open that up and see about 3GB tops in there.

What is this about? thanks.

farhadd · May 26, 2015, 12:52 PM

I would recommend downloading a copy of (free) Disk Inventory X from http://www.derlien.com/ . It's a great tool for figuring out all the hidden junk cluttering your drive. You might have some junk stuck in a .Trash or .Trashes folder at the root level of the drive or in your home directory.

jeff k · May 26, 2015, 01:47 PM

Thanks Far, will look at this.

jeff k · May 26, 2015, 02:09 PM

Ah says wont open as not from developer or trusted source, is there a quick way to bypass that?

OreoCookie · May 26, 2015, 04:26 PM

Control-click the icon and select open: you will be greeted with a dialog asking whether you want to trust the developer.

BTW, you should also have a look at OmniDiskSweeper which is free.

jeff k · May 26, 2015, 05:05 PM

Thanks Oreo,
ok did it.
Omni disc sweeper, says 33GB is being used, yet, Mac HD, says 47 is being used.
Of the 33 Omni list, 3GB is private, which I don't understand: 3GB to var, and 2GB to etc,.....?

Now: Disc Inventory, also says about 34 GB is being used, yet as stated when I command I, the Mac HD, it says used 47GB.

On the right had pane Disc Inventory, says preview.app.document 7GB, and textedit.app.document 4GB, don't get that.

OreoCookie · May 27, 2015, 10:59 AM

Don't muck with /var, keep your spring cleaning to /Applications and /Users.

So first of all, how large is your hard disk and how much free space do you have left?

jeff k · May 27, 2015, 07:01 PM

Thanks Oreo, it's about 60GB, but new weird thing, command i, says 140 TB available. Never seen TB before.

P · May 28, 2015, 03:54 AM

TB is terabytes, the next unit up from gigabytes. It's 1000 gigs when dealing with spinning harddrives and 1024 GB when dealing with anything else.

But I think you should fire up Disk Utility check your disk directory, because I suspect that it (or the free space bitmap) has been damaged, and that that is cause of the problems you're seeing.

jeff k · May 28, 2015, 12:33 PM

Thanks P, the weird TB thing has vanished and it now says GB.
Did verification in DU and says volume is ok.

Still, says it's a 60GB drive, and only 12 GB is available, but when I add up what is being used, it's only 37GB.

OreoCookie · May 28, 2015, 04:30 PM

How do you add up what's being used? There are many hidden directories in OS X that do not appear in the Finder (to prevent the user from fiddling with them). Just swap memory can take us significant amounts of space.

Honestly, 60 GB sounds quite small, I'd spend a bit of money on a new SSD* with 256 GB or so. That'd breathe new life in your machine.

* Of course, you have to tell us what kind of machine to have in order to be sure that it is compatible with SSDs.

jeff k · May 28, 2015, 04:41 PM

I'ts macbook air. Thanks Oreo

I don't load that much up into it really.

I just add up the four folders apps, users etc.

Those softwares that show everything we dont see, did not add up much beyond 37 gigs either...

OreoCookie · May 28, 2015, 04:46 PM

Originally Posted by jeff k

I'ts macbook air. Thanks Oreo

Ah, ok.

Originally Posted by jeff k

I don't load that much up into it really.

Apparently you do, because OS X is complaining to not have enough space. You should have at least 20 GB free. Otherwise just creating swap files can make (almost) you run out of space. When OS X has less than 10 GB of free space to work with, it gets quite slow and flakey.

jeff k · May 28, 2015, 05:01 PM

Ok I thought 10% was the number you want free for hardrives, it's 20%?

But I do have 12GB free it says. So that should be ok on a 60 GB disk.

Occasionally I add new software, but not often. It's just for location work...

Still that assumes I have 48GB free, yet I add up those folders and it says using 37 GB...

You don't mean replace Mac HD? just add a new external?

OreoCookie · May 28, 2015, 05:36 PM

Originally Posted by jeff k

Ok I thought 10% was the number you want free for hardrives, it's 20%?

No, there are two different and independent factors:
(1) Limit by the operating system -- and that is you should at least have 10~20 GB of free space.
(2) For optimal performance, you should have 20-30 % free disk space. (This holds for both, SSDs and hard drives for different reasons). In your case that'd be 12-18 GB again.

Originally Posted by jeff k

But I do have 12GB free it says. So that should be ok on a 60 GB disk.

Nope, that's very, very close to the red line, 10 GB.

Originally Posted by jeff k

Still that assumes I have 48GB free, yet I add up those folders and it says using 37 GB...

If disk utility tells you, you have 12 GB free, then no amount of counting will change that. In almost all circumstances the space taken up by things you can't see from the Finder is hidden for a very good reason and shouldn't be touched — unless you know exactly what you are doing. Note that the amount of free space can fluctuate because OS X will dynamically generate swap files on the fly. It may also use some space for deep sleep (it writes what is in the RAM to disk). If your machines has little RAM (which it does since the Air with 64 GB hard drive was the entry-level model), your machine will definitely generate swap files.

Originally Posted by jeff k

You don't mean replace Mac HD? just add a new external?

No, you should replace the SSD inside your MacBook Air. There are kits for that which aren't too expensive. I'd recommend the 240~256 GB kit.

jeff k · May 28, 2015, 05:45 PM

Thanks Oreo,
So there is about 12 GB being used, that I cannot see, and even those 2 apps do not see?

10% is 6GB right, so I have 20% free?

What is a good bang for the upgrade, please send link, I trust you. Actually make it the minimum price, as I don't need that much space.

I do this myself? Maybe I can find someone on craiglist to do it?

But you do a transfer of some sort?

Pity they supply such a small HD, what is Apple thinking?

OreoCookie · May 28, 2015, 06:12 PM

Originally Posted by jeff k

So there is about 12 GB being used, that I cannot see, and even those 2 apps do not see?

10% is 6GB right, so I have 20% free?

Yes.

Originally Posted by jeff k

What is a good bang for the upgrade, please send link, I trust you.

There was a link in my previous post. The 240 GB kit for a 2010 model including tools costs $170. Make sure you check what MacBook Air you have: go to the Apple menu, select About This Mac and you should see the exact model (it should say something like MacBook Air (11-inch, 2010).

Originally Posted by jeff k

Pity they supply such a small HD, what is Apple thinking?

Yup, they shouldn't have sold that machine with that little disk space, plain and simple.

Mike Wuerthele · May 28, 2015, 06:18 PM

Review - MacBook Air OWC 240 GB Aura Pro SSD Review | MacNN

We looked at the kit a while ago. Pretty nice upgrade.

jeff k · May 29, 2015, 02:10 PM

Thanks well I have 20% not bad?

Still we have not solved why says 37GB is taken yet says 48gb is taken... HIdden stuff? Even those 2 apps can't decipher?

Not in the mood to drop $170 on this, nuts, but will bookmark the info... And not include installation?

Mike Wuerthele · May 29, 2015, 02:59 PM

Well, like the review says, with a machine that can be found on sale for $800 for the new model, you've got to consider the cost to benefit of an upgrade versus buying a new machine and selling the old one.

OreoCookie · May 29, 2015, 04:20 PM

Originally Posted by jeff k

Thanks well I have 20% not bad?

Still we have not solved why says 37GB is taken yet says 48gb is taken... HIdden stuff? Even those 2 apps can't decipher?

You don't give us enough information here, that's why we cannot help you. But if the Finder, Disk Utility or Activity monitor claims that only 12 GB are free, then you should take that seriously — even if you cannot account for all of it.

Originally Posted by jeff k

Not in the mood to drop $170 on this, nuts, but will bookmark the info... And not include installation?

You should upgrade when an upgrade becomes necessary. $170 is a fraction of the cost of a new machine and since it boosts the resale value, the upgrade will actually be cheaper. I reckon you will have a really hard time to sell a MacBook Air with a measly 64 GB of storage. Of course, you could also consider getting another machine, it's quite reasonable to replace a computer after 5 years.