Xcode 12 is slow when launching apps (even sample projects)

Running a project from Xcode 12 seems to be very slow during launch. Even the example projects from Apple.

Basically it feels as if the app is stuck on the launch screen?

However, if I unplug from my Mac and just launch via tapping on the App icon, it's super fast.

Anyone is having the same issue?

Solved Answer

This isn't Xcode 12 specific.

Deleting the contents of ~/Library/Developer/Xcode/iOS DeviceSupport seems to be the fix (worked for me just now):
https://developer.apple.com/forums/thread/123068?answerId=420683022#420683022

28 Replies

Same issue. Running my app from Xcode 12 gets stuck on the launch screen for about a minute. Had this same issue during the Xcode 11 beta.
This isn't Xcode 12 specific.

Deleting the contents of ~/Library/Developer/Xcode/iOS DeviceSupport seems to be the fix (worked for me just now):
https://developer.apple.com/forums/thread/123068?answerId=420683022#420683022
Thanks, deleting the contents seem to work for me.
Same issue for me. Removing iOs DeviceSupport fix the problem for the simulator but when running on a real device (connected to Xcode) it is really slow (stuck on launch screen).
Might be too late, but I ran into this issue after upgrading to Xcode 12.
Going to ~/Library/Developer/Xcode/ and removing contents of "iOS DeviceSupport" did not help so I removed the contents of "iOS Device Logs and "Derived data" too and that resolved it.
Neither deleting Derived Data nor iOS Device Support solved it for me. Any more ideas?
Thank, deleting the contents it work.
I had this too. It took a full minute for the app to launch on the iPhone from the debugger. The phone screen was blank the whole time, and there was no console output. I have no idea what it was doing.

This behavior mysteriously stopped at some point, and the app now deploys in a reasonable amount of time.
I had the same problem. It took a full minute to launch my app on an iPhone from the debugger. The screen was blank the whole time, and there was no debugging-console output. I have no idea what it was doing.

I also have no idea why this behavior suddenly stopped; now the app launches in a reasonable amount of time.
This still happens. I just spent 12 hrs!!!! downloading Xcode 12.01 from the store to replace v12. Now app launches to device take 2 1/2 minutes after launch screen appears. Deleting the specific iOs DeviceSupport folder for the device's version of iOS did the trick. After the folder deletion, Xcode reloaded the symbol tables from the device and all was well. App launch time now back to 1-2 seconds.
1) For simulators run iOS14, delete folders inside ~/Library/Developer/Xcode/iOS DeviceSupport/ (folder's name started with 14.0).

2) For devices run iOS14, select Xcode window tab, click Devices and Simulators, find your device, right-click to unpair the device

https://stackoverflow.com/questions/63929122/slow-app-launch-time-after-updating-to-ios-14-and-xcode-12
Same issue!
Deleting the ~/Library/Developer/Xcode/iOS DeviceSupport directory for iOS 14 did not work for me.
Deleting the ~/Library/Developer/Xcode/iOS DeviceSupport directory content did not work for me. And unpairing the devices over the "Devices and Simulators" panel was not helping either. After successfully loading and running the project on Xcode 12, the app hangs nearly a minute on the app launch image and then run perfectly without errors. The long time is enoying and I hope to find a solution soon! I had this issue since Xcode 12 and iOS 14.
Same issue for me. I had to do these instructions 2 times before the app would launch without hanging for a minute.

1) Unpair your phone from xcode
  • Launch xcode with your phone not plugged in
 - plug your phone in
  • under devices in xcode, unpair your phone
2) stop xcode
3) run these
rm -rf ~/Library/Developer/Xcode/iOS\ DeviceSupport
rm -rf ~/Library/Developer/Xcode/iOS\ Device\ Logs
rm -rf ~/Library/Developer/Xcode/DerivedData
4) start xcode
5) plug phone in