Disk Map: The Answer to ‘Where Did All My File Storage Go?’



When Ms. D’s laptop got a bath of water a few weeks ago in a coffee shop, I got the feeling an emergency Mac switcheroo was afoot; it turned out that the MacBook was lost to water damage and the drive salvageable; so while her 2009 aluminum MacBook’s brain got a temporary reprieve in a 2007 MacBook’s shell, it was clear that she would need a more permanent upgrade.

My typical M.O. is to upgrade me and then give her my machine, and she was all for it for a number of reasons:

  1. My 2010 13-inch MacBook Air was lighter than her MacBook, which she found compelling.
  2. The 2010 could run Mac OS 10.7.x, which is important, because she still needs to be able to use InDesign CS2, which craps out at Mac OS 10.8 and higher.
  3. My old 2010 has a 256GB SSD, and she was coming down from a 400GB internal hard disk, so if she was destined for an Air, she was going to need a decent-sized SSD to squeeze into.

My goal, as usual, was to get something… different. My MacBook Air has been a constant companion for well over a year with nary a complain, but I’ve been eager to try an 11-inch model for sheer portability on sales calls and presentations. Plus, the 2010 was starting to stagger a big under my inevitable load of open windows.

But moving to an 11-inch MacBook Air — and keeping within my budget — was going to mean a smaller SSD; the 11-inch does offer a 256GB, but only in the latest models, meaning more expensive. (I never buy new Macs — sorry Apple. Thanks to making the used ones so great!)

I had to move quickly in this emergency search but found a nice match on eBay within the budget — a 2012 model with 4GB RAM, a faster 128GB SSD, not to mention USB 3.0 and faster graphics than I was accustomed to.

Now… how to get her 350GB of files onto that 256GB — and my 200GB of files onto that 128GB SSD?

Enter Disk Map. I found this little utility a few months ago when I was filling up that 256GB drive and needed to clear up some space to keep from getting “Disk Full” messages. Available for just $3.99 in the Mac App Store, Disk Map can scan your entire drive and give you a visual representation of what, exactly, is taking up space.


What you’ll find is, often unexpectedly, you’ve got something taking up more space than you think.

In my case, with the 256GB drive, it was a massive folder of old e-mail that I don’t refer to anymore in Apple Mail. With everything I need in a webmail account, I could archive that 40GB or so and save a ton of space, but still have it for emergencies. I also found about 20GB worth of GarageBand files (from my Saturday morning karaoke-recording habit) that I could similarly offload to an external drive.

In the shot above, I’m looking at my 11-inch Air’s drive from a few days ago; it’s right at 100GB and, clearly, there’s a nice-sized iPhoto library to consider doing something about, and an extra DropBox folder that I could archive and remove. (Given how tight this Mac is, I’m using Disk Map frequently just to stay on top of things. You can see I’m at 112GB in the shot at the top of this entry, thanks to a current video editing project.)

When I ran Disk Map on Ms. D’s 400GB drive — which only had 50GB open — I found two different disk images that were 80GB each; they were old clones of drives of hers from The Distant Past. Instead of squirreling them away on external drives somewhere, I guess I’d dropped them on her MacBook for easy access. I offloaded those and — 160GB free later — she was already under the cap for moving to her “new” Air.

Aside from its feat of visual magic, Disk Map is pretty basic — you can mouse around to get details on folders and files, and you can delete and compress items and folders directly from the Disk Map interface. But to do anything else — including copy stuff to external drives — you’ll need to use the Show in Finder command. And changes to your disk (like stuff you archive and delete) aren’t rendered live in Disk Map; you’ll need to hit the Reload button to get an updated look at your drive.

But what it does — give you a bird’s-eye view of your hard drive — will probably surprise you with what you’re storing and how much data some things require.

And it’s indispensable if you ever need to squeeze your data from a larger hard disk down to a smaller SSD.

Rating: Highly recommended.

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