Resolve “Your System Has Run Out of Application Memory” on Mac

What is application memory on Mac?

Application memory on macOS is the portion of your physical RAM actively used by apps, frameworks, and system services. Modern macOS also uses compressed memory and swap files—techniques that let macOS stretch limited RAM by compressing inactive pages or writing them to disk.

Activity Monitor’s Memory tab shows “Memory Used”, “Cached Files”, and a “Memory Pressure” graph. Memory Pressure is the best single indicator of whether RAM is the bottleneck: green means healthy, yellow means moderate strain, and red indicates the system is actively paging or swapping, which triggers “Your system has run out of application memory” alerts.

Understanding these terms helps: RAM means fast physical memory, compressed memory reduces RAM footprint, and swap (on your SSD/HDD) stores overflow. If swap grows a lot, performance drops and those alerts appear. The goal is to reduce memory pressure or increase physical RAM depending on your Mac model and workload.

Why macOS displays “Your system has run out of application memory”

That alert occurs when macOS cannot allocate additional memory for apps without severely degrading performance. The system either ran out of free RAM and compression capacity or began thrashing to disk (swap), harming responsiveness. This often happens when one or more apps leak memory or when many memory-hungry apps run concurrently.

Common causes include large browser sessions (many tabs and extensions), runaway processes with memory leaks, poorly built third‑party utilities, background virtualization software, or insufficient physical RAM for your tasks (video editing, large datasets, virtual machines).

Before assuming hardware limits, confirm whether the problem is transient (a misbehaving app) or fundamental (insufficient RAM for your typical workload). Diagnostic steps below help pinpoint the root cause so you can clear memory immediately and apply a lasting fix.

Immediate steps to clear application memory (safe, first-line fixes)

These actions usually resolve the alert quickly without advanced tools. Start with the least disruptive and escalate if necessary.

• Quit or Force Quit memory-hungry apps: Open Activity Monitor → Memory, sort by Memory, select the top consumers, and quit them. If an app is unresponsive, use Force Quit (Apple menu → Force Quit) or use Activity Monitor’s Quit (⌘Q replacement with Force Quit).
• Close browser tabs & extensions: Browsers are common culprits—close unused tabs, disable unnecessary extensions, and restart the browser.
• Restart the Mac: A reboot clears memory, stops rogue processes, and clears compressed memory and swap usage—often the fastest remedy.

When you need command-line tools, use them cautiously. To inspect memory usage in Terminal, run vm_stat to see page activity, or top -o MEM to list processes sorted by memory. If you opt to run maintenance commands, know that sudo purge sometimes frees inactive pages but requires Xcode command-line tools and is not guaranteed on modern macOS releases.

If you need a scripted immediate clear for automation, create a small script that quits nonessential apps and flushes caches, but always test it and warn users before closing apps to prevent data loss.

Preventive fixes and long-term solutions

If alerts recur, apply these durable solutions. They address both software problems and hardware limits so you won’t keep clearing application memory manually.

• Identify and update or remove leaking apps: Use Activity Monitor over time to spot processes whose memory grows continuously. Update those apps or replace them with better-optimized alternatives.
• Reduce background load: Remove unneeded login items (System Settings → Users & Groups → Login Items), turn off heavy background services, and limit browser extensions.
• Increase physical RAM or optimize storage: On upgradeable Macs, increasing RAM is the most effective long-term fix. If your Mac uses swap heavily, ensure you have available free disk space (SSD preferred) because swap on full disks magnifies problems.

Also keep macOS and apps updated—Apple and developers often fix memory leaks. For professional workflows (VMs, pro apps, big datasets), plan hardware upgrades: more RAM and a fast SSD reduce memory-pressure events significantly.

For step-by-step walkthroughs or community scripts that safely target application memory on Mac, consider this GitHub resource: clear application memory on Mac. It contains diagnostic notes and safe cleanup suggestions you can reference while troubleshooting.

Advanced diagnostics: what to check and useful Terminal commands

When immediate fixes don’t stick, collect diagnostics to isolate the issue. Use Activity Monitor over several hours, log when the alert appears, and note active apps at that time. Persistent growth in a single process typically indicates a memory leak.

Key Terminal commands (use with care):

top -o MEM — live list of processes by memory usage.
vm_stat 1 — page/VM activity per second; watch for extensive pageouts.
sysctl hw.memsize — shows installed RAM (bytes).
sudo vm_stat -c 1 — continuous sampling to correlate with alerts.

Avoid gimmicks that promise ‘RAM cleaning’ via third-party apps—macOS manages memory efficiently; third-party cleaners often just flush caches temporarily or misreport freed memory. If you need further help, collect logs from Console.app at the time of the alert and seek help from Apple Support or the app vendor.

For developers diagnosing memory leaks, Instruments (part of Xcode) and Console logs are invaluable for tracking allocations and runaway retain cycles. For non-developers, the practical path is to update, replace, or limit problematic apps and consider hardware upgrades if your workflow exceeds system RAM.

When adding RAM or reinstalling macOS is necessary

If you consistently run into memory pressure and your usage reflects professional or heavy multitasking workloads, consider upgrading RAM (if your Mac supports it) or purchasing a Mac model with more RAM. For example, video editors, developers running multiple VMs, and data scientists often need 32GB+ depending on projects.

Reinstalling macOS is rarely required for memory alerts—use it only when system files appear corrupted or step-by-step troubleshooting (safe mode, SMC/PRAM resets, reinstall) points to OS-level issues. Always back up with Time Machine before major system changes.

Finally, if you’d rather follow a curated checklist and community-tested scripts for diagnosing application memory on Mac, see this project: application memory on mac. It’s a concise companion to the steps in this article.

Quick checklist to run now

Run these in order; each step gets progressively heavier but often resolves the issue early.

1. Open Activity Monitor → Memory, quit top consumers.
2. Close browser tabs, restart the browser.
3. Restart your Mac.
4. If recurring, identify offending apps and update/replace them.
5. If workload demands exceed RAM, plan an upgrade or new machine.

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