Your system has run out of application memory? Here's a fix

macOS is based on Unix, meaning its memory management is pretty robust. However, it's not perfect, so you may still see an error message saying, "Your system has run out of application memory." What does it mean, and why does it happen? We'll explain what causes the error and what to do to fix it.

What does "your system has run out of application memory" mean?

macOS stores data used for active processes in RAM. If space in RAM runs low, macOS starts storing data on your main boot drive and swapping it between there and RAM as needed. This is known as virtual memory. For this reason, you should always have a decent chunk of free space on your boot drive — 10% is a good rule of thumb. If you don't have enough space on your boot drive for an application to store temporary files, you will see the error message telling you your system has run out of application memory.

Why does it happen?

There are a number of things that can cause this error message to appear, although, as we said, macOS memory management is very good, so if you do see the message, you should take action.

Reasons include:

Disk space

Running low on disk space on your boot drive

MultitaskingHaving lots of apps open simultaneously
Browser hanging up

Having lots of browser tabs open

Misbehaving appsSome applications "hogging" memory

The best way to avoid seeing the error message is to make sure you keep as much memory as possible free on your Mac. An Apple-notarized Mac app, CleanMyMac X, has a handy Menu that makes it easy to monitor application memory and free it up anytime you feel like your Mac slows down. Here's how to use it:

  1. Download CleanMyMac X for free here
  2. Install and launch the app.
  3. Go to your menu bar and click the CleanMyMac X icon.
  4. Click Memory.

Your Memory monitor will appear on the left. Here you can monitor how much memory you have available and quit top memory-consuming apps. You can also free up your memory right here: click Free Up in the Memory section to fix all memory issues on your Mac. 

How to fix the "Your system has run out of application memory" error

There are other ways you can tackle the problem, too.

1. Restart your Mac

This is the first thing you should try. Restarting your Mac clears the cache and other temporary files and gives back disk space used as virtual memory. Go to the Apple menu and click Restart.

2. Update macOS

Whenever you run into problems on your Mac, it's a good idea to check if there is an update available in case the problem is a bug and there is a fix for it in the update.

  1. Click the Apple menu and choose About This Mac > More Info.
  2. Choose Software Update.
  3. If there is an update available, follow the instructions on-screen to install it.
    System Preferences - Software Update

3. Use Apple's Storage Management

Apple provides some useful tools to help you manage space on your boot drive.

System Preferences - Storage

  1. Click the Apple menu and select About This Mac > More Info.
  2. Choose the Storage tab.
  3. Check Recommendations, and you will see a list of things Apple recommends you do to free up storage space. Decide which recommendations you want to take and follow the instructions.

4. Update apps

As with macOS, it could be that one or more of the applications you're running has a bug that causes it to hog memory. You should check whether there are updates available for those apps. For apps downloaded from the App Store, you can do that on the Store. For other apps, click the app's name on the top-left corner of your screen (there should be a "Check for Update" option).

5. Close apps you're not using

Keeping apps running in the background when you're not using them uses up a lot of virtual memory. It's good practice to quit apps when you stop using them. Press Option-Command-Esc to open the Force Quit menu. If there are programs you're not currently using, quit them.

6. Close browser tabs

Modern web browsers can have so many tabs open simultaneously that many of us spend all day with dozens of them open. And then we wonder why our Macs are running slowly. Keeping tabs open means they update in the background, taking up memory and other system resources. Bookmark tabs you use regularly and close them when you're finished using them.

How to check the memory on your Mac using Activity Monitor

If you've completed all the steps above and are still getting the same error message, you'll need to do some detective work to track down the source of the problem. macOS has a great tool for this work — Activity Monitor. It allows you to see all processes currently running on your Mac and list them according to the system resources they are consuming, including RAM. In this way, you can see which processes are hogging memory and possibly causing the error message, then quit them.

  1. Go to Applications > Utilities and launch Activity monitor.
  2. Click the Memory tab to see a list of processes that consume memory, including applications and browser tabs.
  3. Select a process or app, and click the "X" sign to close it.
The app we mentioned earlier, CleanMyMac X, has a Maintenance module to help you quickly optimize your Mac. It frees up RAM, purgeable space, runs maintenance scripts, and so much more to keep your Mac's system running smoothly.

7. Review browser extensions

Obsolete or buggy browser extensions could be another cause of memory problems on your Mac that could lead to the same error message. Take a look at the extensions in each web browser and decide whether you use them or whether they can be disabled or removed.

In Safari, you'll find extensions in Settings > Extensions. In Chrome, you can access them by typing chrome://extensions in the address bar.

8. Uninstall applications

Some applications take up several gigabytes of space on your Mac, so if you don't use them, it makes sense to uninstall them. If they were downloaded from the App Store, you could always download them again when you need them. Or, if not, you should be able to re-download them from the developer's website. Did you know, for example, that Microsoft Word takes up to 2GB of space?

9. Install more RAM

The last resort, and the most expensive option, is to install more RAM in your Mac if you can. Having more physical RAM will mean macOS needs to use your boot drive less often to store swap files. However, not all Macs can have RAM upgraded after purchase, and for those that do, it usually means a trip to an Apple Store or an authorized service center.

There are many reasons you might see an error message telling you that your system has run out of application memory. But they all point to the same thing — a shortage of space on your boot drive. So, the simplest solution is to free up more space. However, you should follow the steps above to identify whether there is a problematic app taking up more memory than it should.

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