Hi, when developing with Flutter on the OSX Catalina, you may face this kind of issue when you are running flutter doctor command or run the app into IOS simulator.

Error message : “idevice_id” cannot be opened because the developer cannot be verified.

I found the solution on Github. (Link)

you have to run this command inside your terminal

sudo xattr -d com.apple.quarantine PATH_TO_YOUR_FLUTTER_HOME/bin/cache/artifacts/libimobiledevice/idevice_id

sudo xattr -d com.apple.quarantine PATH_TO_YOUR_FLUTTER_HOME/bin/cache/artifacts/libimobiledevice/ideviceinfo

sudo xattr -d com.apple.quarantine PATH_TO_YOUR_FLUTTER_HOME/bin/cache/artifacts/usbmuxd/iproxy

For example :

sudo xattr -d com.apple.quarantine Developer/flutter/bin/cache/artifacts/libimobiledevice/idevice_id

sudo xattr -d com.apple.quarantine Developer/flutter/bin/cache/artifacts/libimobiledevice/ideviceinfo

sudo xattr -d com.apple.quarantine Developer/flutter/bin/cache/artifacts/usbmuxd/iproxy

After you success run the command, you can retry to run flutter doctor command to verified. If the message box does not appear, the issue has been resolve.