Hello,
We are experiencing a recurring issue when running iOS apps in the Rosetta simulator on Xcode 26.
Environment:
Xcode: 26.0
macOS: 15.7.3
Simulator: Intel-based (Rosetta) simulators
Languages: Both Swift and Objective-C
Issue:
When launching an app in a Rosetta simulator, the app frequently freezes or fails to run. In many cases, Xcode reports that the debugger has lost connection.
Xcode error message:
Lost connection to the debugger on “iPhone 12”.
Domain: IDEDebugSessionErrorDomain
Code: 22
Failure Reason: Message from debugger: lost connection
Console log:
assertion failed: GPR thread_set_state is unimplemented for NewThread
(ThreadContextRegisterState.cpp:920 host_gpr_state_from_guest_state)
Observed behavior:
Rebuilding after fully quitting the simulator sometimes resolves the issue temporarily.
Disabling Scheme > Run > Debug executable allows the app to run normally, but debugging (breakpoints, etc.) becomes unavailable.
The issue does not occur:
On real devices
On ARM-based simulators
When building with Xcode 16 using Rosetta
Has anyone encountered this issue with Xcode 26 and Rosetta simulators? Is this a known bug, and are there any recommended workarounds besides disabling the debugger or restarting the simulator?
Thank you in advance for any insights or guidance.
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