Cached Files

No. Unused RAM does nothing, so macOS puts it to work. When an app needs memory, macOS drops cached data to make room. A large Cached Files number usually means there is plenty of memory to spare.

There is no need. Clearing the cache makes files load from disk again and can make the Mac feel slower until the cache refills. Tools that promise to free memory this way mostly undo what macOS is doing on purpose.

The bottom of Activity Monitor's Memory tab shows Physical Memory, Memory Used, Cached Files and Swap Used. Physical Memory is the RAM installed. Memory Used is what apps and the system are holding. Cached Files is memory holding copies of files that apps can have back whenever they need it.

Together, Memory Used and Cached Files can take up almost all of Physical Memory. That is normal. It means macOS is putting RAM to work instead of leaving it empty.

Apple's guide puts it this way: "macOS obtains the best performance by efficiently using and managing all of your computer's memory." Free memory does not make a Mac faster. Memory that is holding useful data does.

Apple describes Cached Files as the size of files cached into unused memory to improve performance. The figure changes as you work:

• It grows after you open large files, launch apps, copy files or run a backup, because those files are read from disk.
• It stays large while nothing else needs the memory, since cached data remains until it is replaced.
• It shrinks when apps need more memory and macOS hands cached memory over to them.
• It starts small after a restart and fills up again as you use the Mac.

A large Cached Files figure is never the problem. A small one can be a clue. If Cached Files is small, memory pressure is yellow or red, and Swap Used is growing, apps have taken nearly all of the RAM and there is little left for the cache.

In that case, look at the Memory column to find what is using memory, not at the cache. Apple lists file cached memory as one of the inputs to memory pressure, so the graph already takes the cache into account for you.

No. Cached Files in Activity Monitor is memory in RAM. App caches in folders such as ~/Library/Caches are files stored on your disk.

Deleting cache folders on disk does not make your Mac faster in the way people expect, and apps rebuild those caches as you use them. It also does nothing useful for memory pressure.

If what you actually need is more free disk space, open System Settings, choose General, then Storage. It shows what is using space on the disk and suggests ways to free it, which is safer than deleting folders in your Library by hand.