sudo mkdir /private/tmp
sudo chmod 1777 /private/tmp
xcrun
xcrun simctl list devices //to list all simulators
xcrun simctl delete // to delete specific device
xcrun simctl delete unavailable // to remove old devices for runtimes that are no longer supported
Delete and clean
xcrun simctl shutdown all
xcrun simctl delete $(xcrun simctl list | grep -o '[0-9A-F]{8}-[0-9A-F]{4}-[0-9A-F]{4}-[0-9A-F]{4}-[0-9A-F]{12}' | xargs)
xcrun simctl delete unavailable
xcode
sudo xcode-select --reset
To delete devices go here:
~/Library/Developer/CoreSimulator/Devices
Defautl open /Applications/Xcode.app/Contents/Developer/Applications/Simulator.app/
Launch multiple simulators
find simulator id’s from the ‘xcrun simctl list’ command
xcrun simctl boot 12F3C6FB-1A8A-4D20-922F-2DB485F58F0F
xcrun simctl boot BE53CBFF-4900-4F10-A1D4-B451AB4C9E7E
open /Applications/Xcode.app/Contents/Developer/Applications/Simulator.app/
- Go to Window > Devices and Simulators, delete all the simulators, all of them.
- Clear /Library/Developer/CoreSimulator/ folder.
- Return to Xcode and install the required simulators.
Deleting caches should not be necessary here. I expect that will just cause the issue to recur later.
There are a few causes we've identified for this issue:
The dyld_sim shared cache fails to map into a process within the watchdog timer because it was just recently created and is still being scanned by the system. Deleting the cache will momentarilary address this problem, but you would hit it again the next time the cache is created. Waiting ~2 minutes should allow the scan to complete. Additionally, if you update to Xcode 15.3 Beta 2 or later (released last week), we now avoid attempting to use the cache until that scan is complete.
There is a performance issue reading from the simulator runtime disk images which can result in boot triggering that watchdog timer, especially if I/O is competing with the process that is generating the dyld shared cache. This performance issue has been addressed in macOS 14.4 Beta and later.
As such, I reccomend that users facing this issue please update to macOS 14.4 Beta or later and Xcode 15.3 Beta 2 or later. If you still see this issue, please collect the following tarballs and attach them to a report at http://bugreport.apple.com:
xcrun simctl diagnose
sudo sysdiagnose
Also, if you're able, please enable debug logging via:
defaults write com.apple.CoreSimulator DebugLogging -bool YES
(you can remove the debug logging later with defaults delete com.apple.CoreSimulator DebugLogging)
Note that we've had multiple reports of this issue over the past 6 months, but triage has been difficult in part becuase we have not been getting the logging requested above and by the time the reporter gets around to responding to the request, they are out of the problematic state (because it usually resolves on its own in a few minutes). Please do not assume that someone else is providing the data. Thanks!