Memory
Cached files
Recently used data macOS keeps in spare memory so it can open it faster next time.
What it is
Rather than leaving memory empty, macOS keeps recently used files and data there. If an app needs that memory, macOS gives it back immediately.
This is why "Memory Used" can look high on a perfectly healthy Mac.
Should you worry?
Never. Cached files make your Mac faster and are released automatically.
What you can do
- Nothing to do. Apps that promise to "free RAM" by clearing caches usually make things slower.