From 39 GB free to 168 GB on a 256 GB MacBook Air
My 256 GB MacBook Air went from 39 GB free to 168 GB free, and I didn’t delete a single photo, document or project. Nearly all of it was junk in the most boring sense: developer caches and app caches my Mac can rebuild, old installers, and leftovers from apps I no longer use. One scan found 117.45 GB of it.
I’m Irshad, a solo designer and developer, and I built SpaceUp Mac because that MacBook Air was my daily machine. This is the honest version of the story, including the part where the app only exists because I didn’t trust apps like it.
Life at 39 GB free
A 256 GB Mac fills itself. You don’t have to do anything special. You install Xcode, you build a few projects, you run npm install more times than you can count, and one day the “Your disk is almost full” alert becomes a regular visitor.
I did the usual rounds. Emptied Downloads. Deleted old screenshots. Offloaded photos. Every round bought me a little room, and it was gone within a week, because I was cleaning my own files while the real weight sat in folders I never looked at. Storage settings just called it System Data and left me to guess.
That opaque bar is what started this. I wanted to know exactly what was taking the space and why, in plain words, before anything got removed.
What 117.45 GB of junk actually is
When I ran the first real scan on my own machine, it found 117.45 GB of rebuildable junk. Not junk in the scary cleaner-app sense. Junk in the technical sense: files that tools create for their own convenience and recreate on demand.
The big offenders on my Mac:
| What it was | Why it’s safe to clear |
|---|---|
| Xcode DerivedData | Build intermediates and indexes. Xcode rebuilds them the next time you build. |
| iOS DeviceSupport | Debug symbols from every iPhone I’d ever plugged in. Re-extracted when you connect a device. |
| npm and Homebrew caches | Downloaded packages. Re-fetched on the next install. |
| Editor and browser caches | Web caches my code editor and Chrome keep. Rebuilt on the next launch. |
| Logs and old iOS update installers | Logs are written fresh as needed. The installers stopped mattering the day the update finished. |
Notice what’s not on that list: nothing I made, nothing I’d miss. That’s the entire trick, and it’s why I get uneasy when cleaner apps promise magic. There’s no magic. There’s just a lot of cache.
If you want the deeper explanation of this category of files, I wrote it up in the guide to developer junk on a Mac.
Why the app shows you everything first
I’ll be blunt. I thought most cleaner apps were scams before I built one, and I’ve written about why. So the one non-negotiable rule was that SpaceUp Mac never deletes anything without showing it to you first, with a plain reason next to every item.
The review screen is the whole product, really. Safe items are green and pre-ticked, and every row says what the thing is and what happens when it’s gone.
The deletion rules are simple. My own files go to the Trash so I can undo. Rebuildable junk is cleared directly, because trashing gigabytes of cache would just move the problem. The few permanent actions, like removing old iPhone and iPad backups, are labeled permanent before I approve them. I wrote more about that split in why Trash comes first.
The other gigabytes
The scan’s 117.45 GB got me most of the way. The rest came from slower, more deliberate work. Deep Scan surfaced the big files I’d forgotten about, including old installer disk images I’d downloaded once and never opened again, and the uninstaller helped me remove a few apps properly, leftovers included. Those were my files, so they went to the Trash, and I emptied it once I was sure.
None of that was one magic button, and I don’t think it should be. Big personal files deserve a human looking at them.
You can do all of this by hand, for free
This is the part a marketing page wouldn’t say, so I’ll say it here. Everything above is doable manually. Apple’s storage tools in System Settings are genuinely useful, and Apple documents them well. If you’re comfortable in Terminal, the single biggest win on most developer Macs is one line:
rm -rf ~/Library/Developer/Xcode/DerivedData
I keep a full manual walkthrough in the guide to freeing up disk space on a Mac, and it doesn’t require the app at all.
SpaceUp Mac is the same work with a map, a review screen and a reason next to every item. The first scan and first clean are free, so you can check my numbers against your own Mac without paying anything.
Where it landed
168 GB free, up from 39. That’s 129 GB back on a 256 GB machine, and it changes how the computer feels to live with. Not faster, the app makes no speed promises and neither do I. Just roomy. Xcode updates install without a cleanup ritual first. A screen recording doesn’t set off a storage panic.
The caches are growing back, of course. That’s their job, and it’s fine. The difference is that now I know exactly what they are, and clearing them is a short review instead of an afternoon of guessing.