Startup Disk Nearly Full? 6 Space-Saving Tips For Critically Encumbered Macs

Justin Pot 17-07-2013

Free up some space on your Mac’s startup drive. Whether you’re wondering if your full drive is affecting performance or just want some extra room, a few simple steps can free up a lot of space.


It’s a good idea to leave between five and 10 per cent free on your Mac. This is because your Mac uses that space for virtual memory, caches and more. As James pointed out when you taught you how to speed up an old Mac Speed Up an Old Mac with These Tricks [Mac OS X] Given time, the performance of any computer will tend to degrade - even Macs (gasp!). Years of improperly un-installing applications can leave your drive littered with preference files and resources that are no longer needed.... Read More , filling up your boot drive interferes with your computer’s ability to do these things, which will ultimately slow down your machine.

If your drive is too full, and you’re not sure what to do, here are some steps to consider. If you work your way through this guide, you’ll be at the 10 per cent threshold in no time.

Step 1: Empty Your Trash


It’s obvious, sure, but for that reason sometimes you won’t think of it right away. If you regularly delete files – and I know I do – your trash can fill up, quickly. Those files take up space on your drive until you, the user, opt to empty the trash.

Oh, and while we’re doing obvious things: empty your Downloads folder. File everything in there that you need somewhere – anywhere – else, then delete everything else. You’ll be amazed how quickly that folder can get out of hand if you don’t do this regularly.


Step 2: Find And Delete Unnecessary Large Files

If your disk is full, the obvious thing to do is delete files. But which files to delete? If there’s a large file on your drive that you don’t need, that’s the obvious first candidate.

But how you can you quickly figure out which files on your drive are too big? Lucky for you we’ve gone over this before, and pointed out a few choice free applications to analyze and inspect your Mac hard drive The 5 Best Free Apps to Check Disk Space Storage on Mac Here's how to check the disk space on your Mac to find out how much storage space you have and delete large files. Read More . Among the highlights is Grand Perspective, which gives you a visual overview of the files on your drive:

Startup Disk Nearly Full? 6 Space-Saving Tips For Critically Encumbered Macs 03b Picture of hard drive

Use this tool to explore the biggest files and folders on your drive. Is there anything you can afford to delete, or perhaps move to a different drive entirely? If so, you’re well on your way to freeing up vital space on your startup disk.


Step 3: Delete Software Installers

Have you been deleting .DMG files after installing software? Because you don’t need them, and should really be deleting them as you go. Search for “.DMG” files in Finder and you will be given an option to choose “Disk Image” as a file type.

Startup Disk Nearly Full? 6 Space-Saving Tips For Critically Encumbered Macs dmg search


You can then delete any you’re sure you don’t need anymore. If you must save your DMG files, at least move them to an external drive.


Step 4: Run A System Cleaner

Still not enough space on your disk? Well, you can temporarily free up some space by running a cleaner program. There’s a full version of CCleaner for the Mac Full Version of CCleaner Now Released For The Mac No matter how intuitive and reportedly "trouble free" Macs are to run, believe me, several months after you add hundreds of files, applications, and download thousands of webpages, your shiny new iMac or MacBook Air... Read More if you want something simple.

Startup Disk Nearly Full? 6 Space-Saving Tips For Critically Encumbered Macs ccleaner 10

Of course, CCleaner isn’t the only game in town – you can also look into tools like MainMenu or Onyx OnyX Gives Access To All Kinds Of Hidden Mac Options [Mac] Keeping your Mac running in tip-top shape is important. If you use your computer for work, you are going to want it running as fast as possible. Apple actually has all kinds of options available... Read More if you want to clean files and customize other things on you system.

Step 5: Delete Unused Languages And Printer Drivers

Startup Disk Nearly Full? 6 Space-Saving Tips For Critically Encumbered Macs monolingual languages


Is your disk still too full? Maybe your computer speaks too many languages. Monolingual can clean that up for you Monolingual - Remove Languages You Don't Use From Your Mac Free up some space on your Mac – delete languages you will never use. Monolingual is a simple Mac app that anyone looking for more hard drive space should check out. Modern hard drives are... Read More – just pick the languages you want to remove and the software will remove them. You can save as much as 3 GB this way, but be warned: it’s not easily reversible.

Another thing you can do is head to ~/Library/Printers (in Finder, click Go then Connect To Server if you can’t find the folder), then delete any printers you don’t currently own or use. Depending on how many printers you’ve installed in the past, this could free up quite a bit of space.

Step 6: Delete Unwanted Apps

Maybe you noticed this in step 2, but some apps take up a lot of space. Look through your Applications folder and ask yourself: when was the last time I actually used this app? If the answer is “Never,” you might want to delete it – or at least move it to an external drive. Games, in particular, take up a lot of space – consider backing up any you haven’t played lately to an external drive.

Again, this one’s obvious, but it’s worth doing now and then.

Consider Getting A Bigger Drive

There are other tricks you could do to free up some space. You could move your music and photos to an external drive, or a NAS. You could delete any unused footage in iMovie, or delete movies you don’t want anymore.

Ultimately, though, if the above steps haven’t worked, it’s time to face the facts: you need a bigger drive. Consider upgrading your drive if you’ve got a MacBook, or installing another drive if you’ve got a device where that’s possible. Ideally, store your operating system and applications on one drive and your files on another – this will help ensure you don’t fill up your boot drive again.

Do you know of any other space saving techniques for Mac users? Please: share them below. I look forward to reading them.

Related topics: Computer Maintenance, Hard Drive.

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  1. Anonymous
    July 20, 2015 at 5:59 am

    Nice guide. Just another tip here - A free app MacClean can actually do above all tasks, no need to do these jobs manually any more. In my case, it saved around 20GB of space successfully. No issue caused. You can have a try yourself.

  2. Ezra
    December 6, 2013 at 11:06 pm

    Let me clearify, I mean it is acting like the Startup disk is RAM? Is this true? I know I'm new to using OS X, but I don't think it works this way, please help.

  3. Ezra
    December 6, 2013 at 11:03 pm

    My computer says this, then asks me to force quit some of my applications, even though I still have around 6Gbs unused and my hard rive still has 98.9Gbs free left. Why is it doing this?

  4. Luis
    October 25, 2013 at 1:52 am

    I cannot start, how can I do any of these steps?

  5. data recovery
    July 29, 2013 at 9:34 am

    Data recovery is the term used to describe the process of extracting data from a storage device. By storage device I am referring just to the obvious devices such as an internal hard drive, external hard drive, memory sticks, discs and other forms of electronic data storage typically associated with computers, but also the not so obvious devices such as the hard drive in your sky box or the hard drive in your camcorder.

  6. skylar
    July 20, 2013 at 5:01 am

    both windows and OSX suffer virtual memory wise when the root drive gets full, dang, i was thinking OSX had a linux-like approach to virtual memory. you know, separate virtual memory partition.

    • Justin Pot
      July 20, 2013 at 5:25 pm

      Nope, no separate SWAP for Macs. Kind of weird now that I think about it...

      • skylar
        July 22, 2013 at 3:30 am

        i just can't help but think how would it react with the emergency remount root read-only command "ALT+sysrq+u"?

        • Justin Pot
          July 22, 2013 at 2:30 pm

          To be honest I'm not even sure what that does (take away my geek badge if you must) but I'll say there's no "sysrq" on modern Mac keyboards.

        • skylar
          July 22, 2013 at 7:36 pm

          oops! i feel stupid. i'm thinking of the OS that OSX as built off of "openBSD" which runs on pc hardware and shares the command with linux, it might not exist in OSX anymore and if it does you would probably have to use BASH. “ALT+sysrq+u” remounts all mounted drives as read-only,don't worry most linux and BSD dev's don't know the magic-sysrq keys exist, let alone linux/BSD users knowing what they are.

  7. Bruno Casarini
    July 18, 2013 at 2:51 am

    There's also Xslimmer ( I've used it for years, and it's great.

  8. Sassah122 S
    July 17, 2013 at 9:12 pm

    You made a little error in the paragraph about printers. It should be "Go to folder" not "Connect to server". Also CleanMyMac 2 can do all the things Monolingual and CCleaner can do. It's a bit expensive. There is a 500MB trial version though. Also I recommend removal of unnecessary virtual machines. I suggest the simple zip archiving method.

  9. James M. Gross
    July 17, 2013 at 7:28 pm

    Find and delete email attachments.