Simulator devices
A simulator device records settings, installed apps, test data, keychains, and other state for a particular device/runtime combination. Deleting it removes that local test environment. An “unavailable” device references a runtime Xcode can no longer use; it is usually a stronger cleanup candidate than a bootable device used by current tests.
Simulator runtimes
Runtimes are additional Xcode platform components and can be much larger than individual device records. Apple provides Xcode settings and command-line tools to download and manage platform components. Removing a runtime makes every dependent simulator device unavailable until that runtime is installed again.
Physical-device support
DeviceSupport is not a simulator. Xcode uses version-specific support files and symbols when connecting to and debugging physical devices. Old versions may be candidates when you no longer work with those OS versions, but removal can force later regeneration or download and can interrupt debugging older hardware.
A safe review sequence
- Quit Simulator and stop active Xcode test sessions.
- List simulator devices with their runtime availability.
- Prefer devices marked unavailable when their runtime is intentionally gone.
- Review runtime removal in Xcode’s platform-component management.
- Match DeviceSupport versions against physical devices you still debug.
- Preserve test fixtures or local data you cannot recreate.
SpaceLint separates unavailable simulator devices from DeviceSupport and other Xcode data. It uses tool-aware deletion where supported and leaves protected or ambiguous platform data display-only.