What is the ~/Library/Developer folder on Mac, and what's safe to delete?

By Irshad PC · Published September 25, 2026

Location

~/Library/Developer

Safe to delete?

Partly, with care Caches inside rebuild on their own, but Archives and UserData can't be recreated.

~/Library/Developer is where Xcode keeps build files, device symbols, simulators and your archived app builds. Don’t delete the whole folder. Parts of it, like DerivedData and old iOS DeviceSupport folders, rebuild on their own and are safe to clear. Other parts, like Archives and UserData, hold things Xcode can’t recreate.

What is ~/Library/Developer?

It’s a folder in your user Library that Xcode creates and fills as you build, test and run apps. If you’ve never used Xcode, it may be tiny or missing. Don’t confuse it with /Library/Developer at the top level of your disk. That one holds Apple’s Command Line Tools and the simulator runtimes shared by every account on the Mac.

The main subfolders:

You may also see watchOS DeviceSupport, tvOS DeviceSupport and visionOS DeviceSupport next to the iOS one. They work the same way.

Is it safe to delete?

Not as a whole. Deleting ~/Library/Developer throws away your archives, your Xcode customizations and every simulator along with the caches. Treat each part on its own terms.

Rebuildable, safe to clear:

• DerivedData. Apple’s Xcode 26 release notes tell developers to quit Xcode and clean out a project’s DerivedData to work around certain build failures. Xcode recreates it on the next build. You pay with one slow build and a fresh index.
• iOS DeviceSupport. All of it is safe to clear, and old OS versions are the easy win. Any version that doesn’t match a device you still debug on can go, as a developer on Apple’s forums points out. Connect that device again and Xcode copies the symbols back.
• CoreSimulator/Caches. The Simulator refills it the next time it runs.

Your own work, keep it:

• Archives. Apple says you must retain the Xcode archive for each build you distribute, because without it you might not be able to diagnose issues from crash reports. For an app you shipped, the archive may be your only copy of that exact build. Test archives you never distributed can go if you don’t need them.
• UserData. Your Xcode customizations live here, and since Xcode 16 so do your downloaded provisioning profiles. Delete it and those customizations are gone.

Let Xcode handle it:

• CoreSimulator/Devices. It holds your simulators and whatever your apps saved in them during testing, not your projects. An Apple engineer on the developer forums advises managing it through Xcode or the simctl tool instead of deleting files in Finder.
• Toolchains. Deleting one uninstalls that Swift version. You can download it again from swift.org.

Why it gets so big

Xcode doesn’t prune most of this for you. DerivedData gets a new subfolder for every project you open, and projects you abandoned keep theirs. DeviceSupport adds a folder each time a device you connect runs a new OS version. One developer’s Xcode folder held 21 iOS versions, plus 20 watchOS ones. Archives stack up every time you choose Product > Archive, and a forum reply notes that each new Xcode can bring a new set of simulators.

Developers on Apple’s forums have reported this folder reaching almost 90 GB on a 256 GB Mac and 122 GB on another. Simulator runtimes, the full OS images the Simulator boots, aren’t part of that total. They live outside your home folder, in /Library/Developer/CoreSimulator or, on recent Xcode versions, /System/Library/AssetsV2. The CoreSimulator page has the details.

How to clear it yourself

1. Quit Xcode and the Simulator app. In Xcode 27, simulators run in Device Hub, so quit that instead. An Apple engineer recommends quitting Xcode before you delete anything it manages.
2. In Finder, choose Go > Go to Folder (Apple’s steps), enter ~/Library/Developer/Xcode/DerivedData and press Return. Select everything inside and move it to the Trash. In Terminal, rm -rf ~/Library/Developer/Xcode/DerivedData does the same job and skips the Trash.
3. Go to ~/Library/Developer/Xcode/iOS DeviceSupport and move old OS version folders to the Trash. Keep the current ones only to skip the re-copy. The iOS DeviceSupport page walks through it.
4. Empty ~/Library/Developer/CoreSimulator/Caches, then remove old simulators with Xcode’s tools, not Finder. xcrun simctl delete unavailable removes every simulator your current Xcode no longer supports, for good, so check which Xcode is selected first if you have more than one. The CoreSimulator page covers deleting specific simulators.
5. Remove simulator runtimes you don’t need in Xcode > Settings > Components. Click the info button next to a runtime, then Delete (Apple’s guide). Xcode shows how much space you can recover. Runtimes live outside ~/Library/Developer, so the steps above don’t touch them.
6. Review archives in Xcode. Choose Window > Organizer and click Archives. Keep every archive for a version you shipped. For test builds you never distributed, Control-click the archive, choose Show in Finder, and move it to the Trash. If you need the space, copy old shipped archives to an external drive first, then remove them from your Mac.
7. Open Xcode, build a project and connect your device. Once everything works, empty the Trash.

Leave UserData alone, and Toolchains too unless you’re done with a Swift version. Xcode also keeps a cache at ~/Library/Caches/com.apple.dt.Xcode, outside this folder. The developer junk guide covers it along with npm, Gradle and the rest.

What SpaceUp Mac does with it

SpaceUp Mac lists “Xcode DerivedData”, “iOS DeviceSupport” and “Simulator Caches” (the contents of CoreSimulator/Caches) in the Clean tab and in Dev Mode, which appears when SpaceUp Mac detects developer or AI tools, and when you clean, it deletes their contents directly, not to the Trash, including every DeviceSupport version rather than just old ones. Xcode Archives are marked “Can’t undo”, start unticked, are never picked by the All buttons, and get the same direct delete only if you tick them yourself and confirm, and UserData and Toolchains have no cleanup item in the Clean tab. Deep Scan does list the top-level Xcode, CoreSimulator and Toolchains folders once they pass 80 MB, labeled “App / SDK data · review”. CoreSimulator gets Reveal only, never Move to Trash. For Xcode and Toolchains it asks before moving one to the Trash, but moving the Xcode folder would take Archives and UserData with it, so clear the subfolders instead. In the direct download only, the Advisor tab can also delete simulator runtimes and unavailable simulators through Apple’s simctl, which is permanent, and it asks you to confirm first.

Common questions

Can I delete the whole ~/Library/Developer folder?

Don’t. Xcode would recreate the folder, but your archives, provisioning profiles, customizations and simulators would be gone for good. Clear the rebuildable subfolders instead.

Will deleting DerivedData break my projects?

No. Your source code lives in your project folder, not here. The next build takes longer while Xcode regenerates everything.

Does uninstalling Xcode remove this folder?

No. Removing Xcode leaves ~/Library/Developer behind, and an Apple engineer confirmed your archives survive an uninstall. If you’re leaving Xcode for good, copy the archives you still need to another drive first.

Why does Xcode use more space than this folder shows?

Simulator runtimes live outside your home folder, in /Library/Developer/CoreSimulator or, on recent Xcode versions, /System/Library/AssetsV2. You can see and remove them in Xcode > Settings > Components. If a big System Data number sent you here, the System Data guide covers where else space hides.