Guide

Your system has run out of application memory

This Mac message means the apps you have open need more memory than your Mac can give them, even after using the disk as extra memory. It's usually one app, often a browser with many tabs. Here is how to fix it and keep it from coming back.

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  1. 1

    Read the list in the message

    It names the apps that are open and marks any your Mac has paused.
  2. 2

    Quit what you are not using

    Select an app in the list and choose Force Quit, or quit it normally from its menu. Save your work first where you can.
  3. 3

    Check Activity Monitor

    Open Activity Monitor from Applications › Utilities, click Memory, and sort by Memory to see what is using the most.

Why browsers use so much

Every tab is a page in memory
A page keeps its images, scripts and video in memory for as long as the tab is open, even if you have not looked at it for days.
Some pages keep growing
Mail, chat and dashboards keep loading new things while they sit in the background.
Memory pressure is the number to watch
In Activity Monitor's Memory tab, a green graph is fine. Yellow or red means your Mac is short.

Keep tabs from piling up, in Tern

Tern puts tabs you are not using to sleep, so a hundred open tabs do not cost a hundred pages of memory.

Tabs sleep after an hour
A sleeping tab frees its memory and loads again when you open it. Pinned tabs stay in their place while they sleep.
Choose when
Settings › General › Put unused tabs to sleep: after 15 or 30 minutes, 1 or 2 hours, or never.
What stays awake
Tabs on screen, tabs playing sound and tabs the agent is using.

Questions

Will I lose my tabs if I quit the browser?
Most browsers, Tern included, bring your tabs back when you open them again. In Tern, pinned tabs and each Space's tabs are kept.
Do I need more memory?
If the message comes back with only a few apps open, possibly. Check memory pressure in Activity Monitor first: often one app or one page is the cause.
Does restarting help?
Yes, it frees everything. It is the quickest fix when you cannot tell which app is the cause.

Read next

Made for Mac

Tabs that sleep, Spaces and pinned tabs.

Split screen on a Mac

Two windows, or up to four pages, side by side.

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Try Tern on your Mac

Free, for macOS 26 or later. Bring your tabs over in the first minute; the agent runs on your own Claude key.

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