Slow app launch time after updating to iOS 14 and Xcode 12

Question

I noticed that the launch time of my app has increased significantly (it takes a full minute now vs seconds before) since updating my device to iOS 14 and using Xcode 12. I

Answer 1

I also had this problem, here on Xcode Version 12.1 (12A7403).

The proposed solution to "Unpair" the device in Xcode "Devices and Simulators" didn't work for me (and lot's of people here). Xcode simply keeps crashing when trying that. Hard-reset of the device didn't solve it either.

What did the trick for me: Delete the iOS 14.1 folder inside ~/Library/Developer/Xcode/iOS DeviceSupport. Then simply reopen Xcode.

It takes a while for Xcode to "copy cache files" from the iPhone but once that's finally done, normal debug build and run behaviour is back, without the long delay.