Xcode 16, app is unresponsive after launch when debugging

With Xcode 16, I am experiencing something odd when starting apps with debugging. On one phone, after the app is launched (normally, not slow) and the main screen comes up, it takes between 3 and 15 seconds for the app to become responsive. When turning on Hang Detection on the phone, it is clear that there is a hang going on. This happens for all apps, including a new test app created just to reproduce this issue.

It seems like this delay becomes longer and longer the more times I start the app after a reboot. After a few hours of development, usually the delay is more than 10 seconds.

When starting without debugging, everything is normal, both from Xcode and from the home screen.

I have tried many things without success :

  • restarting the Mac
  • restarting the phone
  • toggling developer mode off and on on the phone
  • disabling wifi and bluetooth on the phone and/or Mac
  • removing the app and reinstalling it
  • disabling all diagnostic options in the scheme
  • made sure there is no VPN enabled

There are no relevant log entries in the Xcode console, none in the Console app for the Mac or phone. I see a spike in Activity Monitor for lldb-rpc-server when starting the app, but only around 25% and it drops shortly after.

It does not happen with other devices, just this iPhone 15 Pro. Is there anything else I can try?

Thank you for providing your detailed post and comprehensive list of troubleshooting steps already taken. I've examined your report, and it appears that the issue may be isolated to that particular device.

To further investigate, I would greatly appreciate it if you could grab a sysdiagnose log after the next hang occurrence. This log will contain valuable hang files that may help us identify the root cause.

Once you've collected the sysdiagnose, as a next step, we recommend performing a full reset of the device to its default factory settings. This systematic approach often resolves software-related issues.

Looking forward to hearing from you with the sysdiagnose log and after you've performed the reset.

Thanks for the quick reply. I have created a feedback with the same info as here and a sampe project and sysdiagnose: FB15507457

I didn't know where to file it so I picked Xcode. I can't reset the phone right now but will do it sa soon as I can and follow up.

Xcode 16, app is unresponsive after launch when debugging
 
 
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