Run Out of Application Memory on macOS 27: What It Means and How to Fix It

You’re working as usual when the Mac stalls and a window announces that your system has run out of application memory and you should quit apps you aren’t using. A Force Quit list follows, with paused apps. What confuses people is that this happens on Macs with 16 or 32 GB of memory and on drives with plenty of free space. The original walkthrough comes from MacHabits.

The message isn’t really about how much RAM you have. On Golden Gate it may also show up more readily on certain Macs than before. Below: what triggers it and how to find the cause fast. Before you start, check app compatibility and keep a restorable backup before changing your operating system.

What the warning actually means

Apple silicon Macs share one pool of unified memory between the CPU and GPU. When apps need more than the pool holds, macOS compresses inactive memory and then moves part of it into swap files on the startup drive. That combination normally lets a Mac handle far more than its physical memory suggests, which is why “memory used” in Activity Monitor is often high without any problem.

The warning shows up when that system can’t keep pace. That can happen in two ways.

Cause 1: Not enough free storage for swap

Swap lives on the startup drive. When free space runs low, macOS can’t create more swap files, and memory has nowhere to go. Long-time Apple community experts advise that low free storage can trigger the warning well before the disk is technically full, especially when apps request a lot of virtual memory.

Cause 2: A process requesting enormous amounts of virtual memory

This is the cause that baffles people with plenty of free space. When an app asks macOS for memory address space, the kernel builds page tables to track it, and those page tables sit in memory that can’t be swapped out. If a process leaks, requesting address space over and over without releasing it, the tables keep growing until no real memory is left for anything else. The warning then appears even though the drive has room.

In practice the second cause is usually a single app: a browser with a leaking tab, an Electron app, a container runtime, a virtual machine or a background agent with a bug.

Fix it right now

While the warning is on screen:

1. Read the Force Quit list. Apps using unusual amounts of memory are listed with their usage. The biggest number is your first suspect.
2. Quit the heaviest app you can afford to lose, saving your work first if it responds. Browsers and virtual machines are the usual candidates.
3. Watch Memory Pressure on the Memory tab of Activity Monitor. Once the graph is green again, the immediate trouble is over. You don’t need to restart.

Find the real cause

Once the Mac responds again, spend five minutes finding what triggered the warning, or it will return.

Sort by memory. In Activity Monitor, click the Memory tab, choose View > All Processes and sort by the Memory column. Note the top five.

Watch for growth. Look again ten minutes later. A process that keeps growing while you aren’t using it is a strong leak candidate.

Get a precise reading from Terminal:

top -o mem -l 1 -n 10 -stats pid,command,mem

Then examine a suspect more closely using its process ID:

footprint -p 1234
vmmap --summary 1234 | tail -20

Replace 1234 with the PID. footprint shows how much memory the process really accounts for. vmmap --summary shows how much virtual address space it has reserved. A process with a modest footprint but an enormous virtual size fits the pattern behind cause 2.

Check swap and storage:

sysctl vm.swapusage
ls -lh /System/Volumes/VM
df -h /System/Volumes/Data

Large, growing swap files together with low available space point to cause 1. Plenty of space and the warning anyway points to cause 2.

Common culprits and what to do

Browsers with many tabs. Chromium-based browsers run each tab or extension in its own process, and one misbehaving tab can grow without limit. Find it with the browser’s own task manager and review your extensions.

Electron and web-based apps. Chat, collaboration and AI desktop apps built on web technology bring their own browser engine along. Several at once can claim a large share of memory, and some leak over long sessions. Until they’re fixed, quitting and reopening them daily is a reasonable workaround.

Container and VM apps. Docker Desktop and virtualization tools reserve memory for their virtual machines. Open their settings and lower the allocation to what you really need.

Apps not yet updated for macOS 27. An app that behaved on Tahoe can leak on a new OS release. Check for updates, and if one app is consistently to blame, report it to the developer.

A system process. If an Apple process tops the list, restart, let post-upgrade indexing finish, and if it recurs, report it through Feedback Assistant with a sysdiagnose.

Why 256 GB Macs are more exposed on Golden Gate

This is where cause 1 and the upgrade meet.

On a Mac with a 256 GB drive, Golden Gate’s footprint adds up: the new system, Apple Intelligence models that many users see taking well over the 7 GB Apple lists, System Data temporarily inflated after the upgrade, and local Time Machine snapshots. Every gigabyte they use is a gigabyte swap can’t have.

We haven’t measured this directly, but the logic is simple: a Mac that ran comfortably on Tahoe with 30 GB free might hit the warning on Golden Gate with 12 GB free, running exactly the same apps. If you see the warning on a small drive, check free space before anything else.

Keep at least 15–20% of the drive free. On a 256 GB Mac that’s roughly 40–50 GB. Our storage guide covers safe ways to get there.

Preventing it

• Keep free space healthy, especially after major upgrades.
• Restart now and then. Long uptimes let slow leaks pile up.
• Limit what launches at login in System Settings > General > Login Items & Extensions.
• Watch Memory Pressure, not Memory Used. Occasional yellow is normal. Frequent red means your workload has outgrown your memory or something is leaking.
• Report repeat offenders. Leaks get fixed when developers receive specific reports.

For the original step-by-step version, see the MacHabits guide to the out-of-application-memory warning on macOS 27.

The short version

• The warning means memory plus swap can’t keep up, not necessarily that your RAM is small.
• Cause 1: too little free storage for swap. Cause 2: a process reserving huge amounts of virtual memory.
• Quit the biggest app in the Force Quit list, then find the real culprit with Activity Monitor, footprint and vmmap.
• On 256 GB Macs running Golden Gate, check free space first.

More on this warning: out of application memory on macOS 27, explained on MacHabits.

Source: https://machabits.info/articles/run-out-of-application-memory-macos-27