Memory
Swap used
Data macOS has moved from memory to the disk because memory was full.
What it is
When apps need more memory than is available, macOS moves some data that isn't being used right now onto the startup disk. That's swap. Reading it back is much slower than reading memory.
Activity Monitor shows the amount under "Swap Used" in the Memory tab.
Should you worry?
A little swap is normal, especially if the Mac has been running for days. Swap that keeps growing while memory pressure is red is what slows a Mac down.
What you can do
- Quit memory-heavy apps.
- Restart to clear accumulated swap.
- Keep free disk space available; swap needs room on the startup disk.
Related terms
Guides
Memory
What is memory pressure on a Mac? Green, yellow and red explained
Memory pressure shows how hard macOS is working to give apps memory. Learn what green, yellow and red mean, why “memory used” is misleading, and when more RAM helps.
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MemoryHow to free up RAM on a Mac (what actually works)
The ways to free up memory on a Mac that actually help, why "RAM cleaner" apps don't, and how to tell whether your Mac really needs more memory.
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