Error: Unable to boot the Simulator

Question

Created May ’20

Replies 5

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I'm having an issue that I can't quite figure out. I'm new to Swift and Xcode, I set up Xcode last week and it worked fine all week.

Then today I started getting an issue when I click on any storyboard in any project where it takes aprox 20 seconds of spinning before it loads and a long time when I try to change anything. The projects I created last week don't display properly anymore, no images, text fields resized to be unreadable. I even made a hello world project and added just one object (I tried different types) and I still get "Internal error occurred. Editing functionality maybe limited" and the link to report a bug has no file. When I try to build the project the project succeeds, but I get the following error:

Details

Unable to boot the Simulator.

Domain: NSPOSIXErrorDomain

Code: 60

Failure Reason: launchd failed to respond.

--

System Information

macOS Version 10.15.4 (Build 19E287)

Xcode 11.4.1 (16137)

When I try to build selecting my iPhone and putting in my team, it says device not available (however I did not try this last week).

I tried restarting my computer, I tried reinstalling Xcode and deleting files, but I clearly missed some because when I started up it opened the last project I had open befre I deleted. I tried resetting the NVRAM. I tried cleaning the build folder. I tried deleting the derived data. I tried deleting and reinstalling all the simulators.

The only thing I can think of that would be different from last week is I changed my Apple ID login, but I'm not even using a developer license yet, I'm just trying to use the simulator and was leaving it blank, so I wouldn't *think* that would matter.

Any suggestions woule be greatly appreciated, thanks!

Edit: I deleted Xcode and tried installing Xcode 10.2.1 and still having the same issue

Boost

Answer 1

KMT OP

May ’20

Suggest you run the Simulator first, keep/icon/in/dock makes that easier.

Otherwise, pls. talk about your mac...how much physical ram, how much free space on what total capacity SSD, are you using a VM, etc.

>The only thing I can think of that would be different from last week is

One week makes all the difference when working with Xcode's free provisioning. See this thread [how i can have free Developer Program ] with an already moderated link that explains Xcode's free provisioning process (with screenshots) - be sure to read all the way thru it and any updates at the bottom. Good luck.

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Answer 2

BrGh OP

Aug ’20

My solution was very, I just first time run and same as yours failed then next time from menu bar I hit Start without building.

That works for me 🙋‍♂️

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Answer 3

RareAnshh OP

Jan ’24

In My case

in Menu Bar -> Product -> Clean Build Folder

Wait for the success message.

Try Again building.

Happy Coding ;)

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Answer 4

Developer Tools Engineer OP

Apple

Feb ’24

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!

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Answer 5

argonneSoft OP

Apr ’24

This solution worked for me: update to macOS 14.4 Beta or later and Xcode 15.3 Beta 2 or later.

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