What the beach ball actually means
Every Mac app handles your clicks and keystrokes one at a time. When an app is busy with something else, such as a slow file, a network request or a bug, it stops responding, and after a few seconds macOS shows the beach ball over its windows. Other apps usually keep working normally.
How to fix a frozen app
- Wait 30 seconds. Many apps are just slow, such as when saving a big file or waking a network drive, and recover on their own.
- Force Quit it. Press ⌥ ⌘ Esc (or choose Apple menu › Force Quit), select the app, and click Force Quit. Unsaved changes in that app may be lost.
- Check Activity Monitor. Apps that aren't responding show (Not Responding) in red. Select one and click ✕ to quit it from there.
- Reopen and update the app. If it keeps happening, check for an update. Freezes are often bugs that get fixed.
If you see the beach ball everywhere
When every app stalls, the cause is usually system-wide:
- Memory is full. Check the Memory tab: a red memory pressure graph means macOS is swapping. Quit some apps.
- The disk is nearly full. macOS needs free space for swap and caches. Check System Settings › General › Storage.
- A slow external or network drive. An app reading a sleeping drive can freeze until it wakes.
- Heavy CPU load. Something maxing out the processor can slow everything. Check the CPU tab.
If it continues, restart your Mac. As a last step, start up in safe mode, which loads only what macOS needs and tells you whether a login item or extension is to blame.