How to Fix ‘Your System Has Run Out of Application Memory’ on Mac

Working on your Mac only to be suddenly interrupted by an ominous full-screen dialogue declaring “Your system has run out of application memory” alongside a Force Quit Applications window is deeply frustrating. macOS demands that you immediately terminate open programs to recover system memory, often freezing your active workspace until action is taken.

This alert occurs when your Mac’s virtual memory subsystem is completely exhausted. In modern versions of macOS (such as macOS Sequoia, Sonoma, and Ventura running on Apple Silicon or Intel), physical RAM is supplemented by dynamic disk swap space. When an application suffers from a severe JavaScript memory leak, an unoptimised video editing render loop, or when your internal SSD runs dangerously low on free storage space, macOS can no longer allocate virtual memory pages. This guide explains how to identify memory-leaking software, manage swap files, and prevent system memory lockups.

Method 1: Identify Memory Leaks via Activity Monitor

macOS features an indispensable diagnostic utility called Activity Monitor. It reveals the exact memory footprint of every open app and background daemon, highlighting rogue processes consuming tens of gigabytes of RAM.

1. Press Command + Space to open Spotlight, type Activity Monitor, and press Enter.
2. Click the Memory tab at the top of the window.
3. Click the Memory column header to sort all active processes in descending order.
4. Review the list. Look for any single application consuming abnormal amounts of memory (for example, a browser helper process, email client, or creative tool consuming 15GB to 50GB on an 8GB or 16GB Mac). This is the hallmark of a memory leak.
5. Select the leaking application from the list.
6. Click the Stop (X) button in the top toolbar and select Force Quit.
7. Observe the Memory Pressure graph at the bottom of the window: once the culprit is terminated, the graph should shift from red/amber back to green.

Method 2: Free Up Crucial Internal SSD Storage for Virtual Swap Memory

When physical Unified Memory or RAM fills up, macOS relies on your internal drive as virtual swap memory. If your internal SSD has less than 15GB to 20GB of free space, macOS cannot create swap files, triggering the “out of memory” alert even under moderate workloads.

1. Click the Apple menu () in the top-left corner and select System Settings.
2. Navigate to General > Storage.
3. Review the storage bar. If your available disk capacity is below 20GB, memory allocation crashes are inevitable.
4. Under the storage recommendations, empty the Trash automatically.
5. Click the info (i) icons next to Applications, Documents, and macOS / System Data to delete unneeded video project caches, iOS device backups, or large installers.
6. Aim to maintain at least 15% to 20% of your total drive capacity as free space to provide dynamic swap overhead.

Method 3: Disable Unnecessary Login Items and Background Daemons

Background utilities that launch automatically upon system startup continuously consume memory buffers, eroding available headroom before you even begin your daily tasks.

1. Open System Settings > General > Login Items & Extensions.
2. Under the Open at Login section, select non-essential applications and click the minus (–) button to remove them.
3. Under the Allow in the Background section, review the list of third-party background daemons.
4. Toggle off background updaters and utilities for applications you rarely use.
5. Restart your Mac to ensure a clean boot with minimal background memory consumption.

Method 4: Boot into Safe Mode to Clear System Font and Kernel Caches

Corrupted font caches, defective display scaling profiles, or third-party kernel extensions can cause macOS WindowServer to experience memory bloat. Booting into Safe Mode automatically flushes these caches.

1. On Apple Silicon Macs (M1/M2/M3/M4): Shut down your Mac. Press and hold the Power button until “Loading startup options” appears. Select your startup disk, press and hold the Shift key, and click Continue in Safe Mode.
2. On Intel Macs: Shut down the Mac. Power it on and immediately press and hold the Shift key until the login window appears.
3. Log in to your Mac (you will see “Safe Boot” in red in the top-right corner).
4. Leave your Mac running in Safe Mode for 5 minutes while macOS executes internal directory checks and purges system caches.
5. Restart your Mac normally.

macOS Application Memory Diagnostics Reference Table

Refer to this reference matrix to identify specific triggers of application memory exhaustion:

Observed Symptom	Underlying Root Cause	Recommended Action
WindowServer process consumes 10GB+ RAM	Memory leak in custom cursor, display scaling, or wallpaper	Revert to default cursor size; boot into Safe Mode
Web browser crashes with out of memory dialogue	Runaway JavaScript leak on open browser tab	Inspect Activity Monitor; close rogue tab
Error strikes when rendering 4K video	Render cache exceeded internal SSD swap space	Change scratch disk to external high-speed SSD
Memory pressure stays in red with few apps open	Background daemon memory leak (e.g., cloud sync tool)	Audit Activity Monitor Memory tab; update software
Frequent memory alerts on 8GB Unified Memory Mac	SSD nearly full, preventing swap file allocation	Free at least 25GB of internal SSD storage

Understanding the macOS Memory Pressure Graph

In Activity Monitor, the total amount of RAM used is less important than the Memory Pressure indicator at the bottom of the screen. macOS is architected to utilize available RAM as disk cache to accelerate app responsiveness. If the graph is Green, memory usage is healthy regardless of how much RAM is filled. If the graph displays Yellow or Red, the memory management system has exhausted available swap and requires terminating high-consumption processes immediately.