问题
I have just installed iOS 14 beta and updated Xcode to latest Version 12 beta 3.
I get an error like *Unable to locate DeviceSupport directory with suffix 'DeveloperDiskImage.dmg'. This probably means you don't have Xcode installed, you will need to launch the app manually and logging output will not be shown! Could not run build/ios/iphoneos/Runner.app on 00008020-001338A20E01002E. Try launching Xcode and selecting "Product > Run" to fix the problem: open ios/Runner.xcworkspace* when I run app from flutter.
I am able to run the app from Xcode but the app won't open / app crashes once USB Cable is disconnected.
Please Help me to figure out what's the issue and work around
回答1:
I had the same problem with Xcode 11.5 I go to https://github.com/filsv/iPhoneOSDeviceSupport, download iOS 14, then copy and paste into /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/DeviceSupport/. It works fine.
来源：https://stackoverflow.com/questions/63198476/unable-to-run-ios-app-on-ios-14-with-flutter