How to delete old iOS simulator runtimes on a Mac

Runtimes vs simulators

A runtime is a whole iOS, watchOS, tvOS or visionOS version for the simulator. A simulator (device) is one iPhone or iPad that uses a runtime, with its own apps and data. On the Mac Derived was built on, three iOS runtimes took about 8 GB each, and the 24 simulator devices another 24 GB.

Since Xcode 15, runtimes live in a system location as disk images, not inside ~/Library. Deleting files there by hand isn't the way to remove them; use Apple's simctl tool instead.

See what you have

xcrun simctl runtime list

This lists each installed runtime with its identifier and state. For sizes and when each was last used, use the JSON version:

xcrun simctl runtime list -j

Look for sizeBytes and lastUsedAt. You can also see installed platforms in Xcode › Settings › Components, which is also where you download a runtime again.

Delete a runtime

1. Quit Simulator, or shut down any simulator that uses the runtime.
2. Check what would happen:

   xcrun simctl runtime delete <identifier> --dry-run

3. Delete it:

   xcrun simctl runtime delete <identifier>

To remove every runtime you haven't used in six months in one go:

xcrun simctl runtime delete --notUsedSinceDays 180 --dry-run

Drop --dry-run when the list looks right.

Delete old simulator devices too

Simulators whose runtime is gone stay listed as unavailable and keep their data. Remove all of them with:

xcrun simctl delete unavailable

Each device's data lives in ~/Library/Developer/CoreSimulator/Devices/<UDID>. One heavily used iPhone simulator on our test Mac held 12 GB on its own.

Command	What it does
xcrun simctl runtime list	Lists installed runtimes
xcrun simctl runtime delete <id> --dry-run	Shows what deleting would do
xcrun simctl runtime delete --notUsedSinceDays 180	Deletes runtimes unused for 180 days
xcrun simctl delete unavailable	Deletes simulators whose runtime is gone
xcrun simctl delete <udid>	Deletes one simulator and its data