Notes on keeping a Mac fast
No tricks, no registry cleaners, no scare tactics. Just what the numbers mean and what is genuinely safe to do about them.
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21 October 2026Your Mac is not slow. Something on it is.
That beach ball is not your Mac dying. It is one process holding 14 GB that Activity Monitor shows as 200 MB. Here is how to find it, why it hides, and what to do.
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29 September 2026Why are my Mac fans so loud?
Loud fans are a symptom, not a fault. How to find what is actually making them spin in about a minute, and when the noise is nothing to worry about.
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29 September 2026Why is my Mac battery draining so fast?
Two different problems wear the same symptom: an app misbehaving, or a battery that has aged. Ten seconds of looking tells you which one you have.
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29 September 2026What is WindowServer, and why is it using so much CPU?
WindowServer draws everything you see. Why it climbs, why external displays and scaled resolutions make it worse, and what actually brings it down.
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21 September 2026Is it safe to delete DerivedData?
Yes, when Xcode is not building. What DerivedData actually holds, what deleting it costs you in rebuild and indexing time, and the one situation where it does real damage.
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21 September 2026Can you clean your Mac while Final Cut is open?
Render files and optimised media look exactly like junk to a cleanup tool. What is genuinely safe to clear during an edit, and what will cost you a re-render.
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21 September 2026What is System Data on a Mac, and why is it 200 GB?
System Data is not a category, it is the leftovers bin in Apple's storage chart. What is really in there, and which parts you can safely get back.
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21 September 2026Free Mac cleanup tools that are actually free
An honest look at the free options for watching and cleaning a Mac, what each is genuinely good at, and where the free tier usually stops.
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19 September 2026Never let a cleaner run during a build
Cleanup tools delete build caches because they rebuild. That is true, unless the build is running right now. Here is why it breaks and what a tool should do instead.
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15 September 2026What is safe to delete on a Mac, and what absolutely is not
A practical list of what you can clear to free disk space on a Mac, what regenerates by itself, and the folders that look like junk but will cost you work.
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8 September 2026Memory pressure and swap on a Mac, explained properly
Your Mac says 15 GB of 16 GB used and people panic. That number is meaningless on its own. Memory pressure and swap are the two that actually matter.
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1 September 2026What is kernel_task, and why is it using 400% CPU?
kernel_task showing huge CPU use is not a virus and not a bug. It is macOS deliberately keeping your Mac cool. Here is what it actually means and what to do.
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24 August 2026Why is my Mac slow all of a sudden?
A Mac that was fine last week and crawling today usually has one of four causes. Here is how to tell which one you have, in about two minutes, without installing anything.