Your System Has Run Out of Application Memory on Mac: What It Means and How to Fix It

"Your system has run out of application memory" is the Mac's way of saying it has nowhere left to put things. Apps freeze, the Force Quit window opens with a list of paused apps, and the spinning wheel takes over. On r/MacOS, people post about it every few weeks, often with the same guess: "I think it's Chrome."

Sometimes it is. Often it is not, and the only way to know is to look. This guide explains what the message means, shows what we found when we measured our own 16 GB Mac, and gives the fix in the order that works: right now, then for good.

The short answer#

• Quit the biggest app in the Force Quit window. Save your work first if you can.
• Find the real cause in Activity Monitor, sorted by Memory. Add up Chrome's helpers.
• Free disk space if your startup disk is nearly full. Swap lives there.
• Red Memory Pressure every day means too much for your RAM. Run fewer heavy apps at once.

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

Your Mac has two ways to stretch its RAM before it gives up. Apple's Activity Monitor guide describes both:

1. Compressed memory. As the Mac nears its limit, it compresses memory from inactive apps to make room.
2. Swap. It moves memory it is not using right now to swap files on your startup disk.

The message appears when both are not enough: RAM is full, compression is not freeing enough, and swap cannot grow fast enough or has no room. macOS then pauses apps and opens the Force Quit Applications window so you can choose one to close. It is not a crash and it does not damage anything. It is the Mac asking you to make a choice it cannot make for you.

Why does my Mac keep running out of memory?#

Four causes cover almost every case:

The third one surprises people. In January 2026, an r/MacOS user got the message with normal Memory Pressure while downloading a huge file. Swap lives on the startup disk, so a disk that fills up suddenly leaves no room for it. That is our reading of the thread, not something the poster confirmed, but it fits the timing exactly.

Is Chrome to blame? What we measured#

Tested on our MacBook Pro (M1 Pro) with 16 GB of RAM, macOS 26.3, October 21, 2026, during a normal working day.

We read the memory of every process with macOS's top tool and added up Chrome's processes as one app:

At the same moment, the Mac was using 16.4 GB of swap, more than its entire RAM.

Chrome was not the problem here. Two emulators held 13.7 GB between them, more than four times all of Chrome. But Chrome is easy to blame: Activity Monitor lists it as dozens of separate "Google Chrome Helper" rows, the biggest only 749 MB. You have to add them up to see Chrome's real total, and you have to look at everything else to see whether it is actually the largest.

How many tabs does it take?#

Chrome can still be the cause on a Mac that runs mainly a browser. To see how memory grows, we opened Wikipedia's home page in a fresh Chrome test profile, again and again in new tabs, and measured Chrome's total memory after 35 seconds:

That is a light page. Twenty copies of it took almost 2 GB. Web apps like Gmail, Slack, Figma or YouTube use far more per tab, so 40 everyday tabs on an 8 GB MacBook Air is enough to trigger the message on its own.

How to fix it right now#

1. Quit one app from the Force Quit window#

1. If any app still responds, save your work there first. A force quit loses unsaved changes.
2. In the Force Quit Applications window, select the app you can most easily lose. Apps marked Paused are the ones macOS stopped.
3. Click Force Quit. If the window is gone, press Option+Command+Esc to open it again.

Quitting one large app usually clears the message within seconds.

2. Find what is actually using the memory#

1. Open Activity Monitor (Command+Space, type Activity Monitor).
2. Click the Memory tab, then the Memory column to sort the biggest first.
3. Look at the bottom panel: Memory Pressure, Swap Used and Compressed.
4. For Chrome, scroll through every Google Chrome Helper row, or open Chrome's own Window, then Task Manager menu to see which tab or extension each one is.

If one app sits far above the rest and keeps growing while you watch, quit it and reopen it. Apps that slowly take more and more memory over hours are a common cause.

Activity Monitor shows Chrome, emulators and dev tools as dozens of separate rows, which makes the real totals hard to see. RAM Rescue, a free and open-source Mac app we make, shows each app as one card with its total memory and a Quit button, counting Chrome with all its helpers as one app. It also finds development servers and processes left running by terminals you already closed.

3. Restart the Mac#

If several apps are paused and you cannot tell which one to quit, restart. Every app closes, swap is cleared, and memory starts fresh. It fixes today, not tomorrow, so do step 2 after the restart when things build up again.

4. Free up space on your startup disk#

Swap needs room on the startup disk.

1. Open System Settings, then General, then Storage, and see how much space is free.
2. If it is nearly full, empty the Trash, move or delete large files in Downloads, and remove apps you no longer use.
3. Check browser and app caches. Our guide to Chrome taking up too much space shows where Chrome alone can keep 20 GB or more.

How to stop it from coming back#

• Keep Chrome lean. Turn on Memory Saver under Settings, then Performance, and close duplicate tabs. Our guide to Chrome using too much memory covers every fix.
• Do not run several heavy tools at once. Emulators, virtual machines, video editors and big design files each want gigabytes. Quit the ones you are not using.
• Quit, do not just close windows. On a Mac, closing an app's last window often leaves the app running. Press Command+Q.
• Watch the trend, not the moment. Glance at Memory Pressure in Activity Monitor once in a while. Green is fine.

Do I need more RAM?#

Apple's guide is direct about the graph: green means the Mac is using its RAM efficiently, yellow means it might eventually need more, and red means it needs more RAM.

If Memory Pressure is red on a normal day, with only the apps you really need open, your work has outgrown the Mac. Most Macs with Apple silicon cannot be upgraded. Apple suggests checking System Information, then Memory, for Upgradeable Memory before you plan anything. If it says no, the realistic choices are fewer heavy apps at once, lighter alternatives for the biggest ones, or a Mac with more memory next time.

If your Mac is slow but the memory is fine, the cause is elsewhere: for a busy processor, see Chrome high CPU usage.