Since the latest Xcode has become available users in our environment are seeing this error any time they try to launch a simulator (Primarily iOS devices, but others provided the same error) We have tested on 16.4 and 26.0.1 with various suggested fixes including uninstalling and reinstalling all of Xcode. Nothing has helped.
The operation couldn’t be completed. (Mach error -308 - (ipc/mig) server died)
Thank you for sharing your post. To assist you further, and find the correct person to help you, could you please provide additional information about your environment, including all the versions you are using? Additionally, please describe the steps you take to reproduce the issue. If you are attempting to deploy code to the simulator, please include any relevant code snippets. It is possible that the issue is related to the version of the simulator you are using.
To download the iOS 26 Simulator, run:
xcodebuild -downloadPlatform iOS -exportPath ~/Downloads -buildVersion 26
If the issue is part of CoreDevice, another engineer can review your answer with more expertise than I possess.
Albert Pascual Worldwide Developer Relations.
macOS: 15.6 XCode 26 iOS 26
Steps to Reproduce:
Click on Simulator -> Devices-> iPhone 16 (or any other iPhone version). It just crashes
Have also tested on 15.7.1 with 26.0.1 Xcode
Thank you for your assistance. The Simulator only has a Device menu, which does not provide any other options to change devices. Xcode, on the other hand, allows you to change devices in the target. Therefore, let’s attempt to identify the root cause of this issue. To do so, we should start by creating a reproducible case and a crash file that can be analyzed or at least used to generate a bug report.
If you have the mentioned crash file. Kindly submit a comprehensive crash report, adhering to the guidelines outlined in Posting a Crash Report.
https://developer.apple.com/forums/thread/688669
If not a reproducible screen recording will be appreciated as well so I can reproduce it in my machine.
Thanks again for all your help.
Albert Pascual Worldwide Developer Relations.
Any ideas as to what may be the cause based off these logs?
None of this crash files are from your app or Xcode? What app is giving you the error Mach error -308 - (ipc/mig) server died)?
Albert Pascual Worldwide Developer Relations.
It's when running the test project in Xcode to launch a simulator. The crashes are from Simulator.app. I didn't see any for Xcode specifically.
This issue persists on latest beta's too
Any details can be found at FB20571413 👀
DLP Tooling was unmounting the simulators from diskutil.
Closing this loop.