Guides

Cached files in Mac memory

It is several gigabytes, it is counted as used, and it is doing you a favour. Emptying it is the one action guaranteed to make things worse.

Last updated September 11, 2026 · by the RAMKeeper team

Apple's definition is short: cached files are "memory that was recently used by apps and is now available for use by other apps."

Read that twice, because both halves matter. It was used. It is available. Those two facts together are why the figure is large, why it is counted in "memory used", and why every instinct to shrink it is wrong.

What is actually in there

Files you have read recently: application binaries, frameworks, fonts, images, the contents of documents you opened. macOS keeps them in RAM after it is finished with them, because the alternative is reading them off disk again the next time. If another app needs that memory, the system takes it back immediately and without asking.

It is not a leak, not a cleanup task, and not a queue of files waiting for you to delete them. It is the operating system spending memory you were not using on making the next few seconds faster.

A measured reading

From the machine these guides are measured on, 11 September 2026, via vm_stat:

Nearly 14 GB of cached file data on a machine reporting 0.71 GB free. Both figures are correct, and the machine was not under pressure: swap usage was zero.

"How do I reduce cached files?"

You do not, and this is the part worth being blunt about: reducing it is a cost, not a saving.

Every page you evict from the cache is a page macOS has to read from disk again the next time something wants it. You have not freed memory in any sense that helps you; you have converted memory you were not short of into disk reads you now have to wait for.

There is a command that does it, sudo purge, and it exists for developers who need a cold cache to measure against. Running it because a number looked high means deliberately throwing away work your Mac already did for you. If you want to see the effect, run it and watch how quickly the figure climbs back: that climb is the cost being paid again.

The same argument applies to any app whose selling point is emptying caches on a schedule. We measured what those tools actually change.

Then which number should worry you?

Memory pressure, and nothing else in this pane. Pressure accounts for free memory, swap rate, wired memory and cached files together, and it answers the question you actually have: is memory keeping up. Green under your real workload means yes, whatever the individual categories look like.

Two sibling figures are worth knowing for the same reason: wired memory, which cannot be paged out at all and has no process to blame, and compressed memory, which is macOS trading a little CPU for a lot of RAM. On the reading above, the compressor was holding 21.3 GB of data in 10.9 GB of physical memory.

When cached files are genuinely a symptom

One case: if a very large cached-files figure sits next to rising swap and yellow or red pressure, the cache is not the problem but it is telling you the system is juggling. That combination means the demand exceeded what the machine has, and macOS is reclaiming cache to keep up. Look at what is demanding it rather than at the cache: how to take the per-app reading, and how to turn a week of those into a decision.

The short version

• Cached files are recently read file data kept in RAM in case you need it again.
• They count as used and are available at the same time. Both are true.
• On the measured machine: 13.87 GB cached, 0.71 GB free, zero swap. That is healthy.
• Reducing them buys you disk reads, not memory. sudo purge is for benchmarking.
• Watch pressure. It is the only figure here that answers a question you have.

Disclosure: published by RAMKeeper, which sells a Mac memory tool. RAMKeeper does not clear caches and nothing here recommends doing so. All figures came from vm_stat on 11 September 2026.