Xcode “failed to prepare device for development”

I’m trying to test my app on the phone using Devices and Simulators in Xcode. Under errors and warnings, I see the message “failed to prepare device for development”.

Xcode version 13.2

There’s an update on my phone I’m running now 15.4.1. It’s currently 15.4, so not sure if this will help

Has anyone else come across this? Any ideas on what to do? I’ve already restarted the phone twice. Saw this on stackoverflow but doesn’t seem to help

Since you run on iOS 15.4 I imagine you need to update Xcode to version 13.3. But I can be wrong.

I wondered that too. I’ll give that a try tomorrow

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Just in case it helps, I’ve had this twice now when I hadn’t entered a PIN on my Apple Watch to trust Xcode. The solution for me was to remove the iPhone from XCode (right-click on it and choose remove in Devices & Simulators), restart everything and then pair the phone again, this time being sure to enter my PIN on the Watch when prompted to trust. I found that tip on Stackoverflow too, but a little further down and it wasn’t the up-voted tip but did work for me.

Thanks for the tip Jason. Can you tell me what version of Xcode and phone you have? I didn’t get a chance to try the updating Xcode yet. That process usually takes me several hours. Just curious if it is necessary to go from 13.2 to the current build

I have not recently done iOS work in Xojo, but in my experience the problem with connecting to iOS devices after an iOS upgrade is more often the “iOS Device Support” files needed for XCode to connect to an iOS release later than your XCode build. And those are relatively small.

People traditionally get those files by downloading a new XCode build (which has them included), but if you have a slow internet connection and want to try just installing these support files, there is a GitHub site I keep bookmarked where you can get them. The site also has some docs on what to do with them, if you are not familiar with these files.

This isn’t my page; just something that I’ve used in the past with other toolsets. They have device support files for up to iOS 15.4 from XCode 13.3; check it out here and you can get support files from iOS 8.0 to 15.4 but no point in getting more than you need.

Xcode 13.3 and an iPhone 13 Pro running iOS 15.4. I think you’ll want to be on 13.3 if you have iOS 15.

Thanks guys! Guess I know what I’ll be doing tomorrow :slight_smile:

Updating Xcode did the trick!

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