Flutter App Running Error: Dart can not be opened, Developer can not be verified after upgrading to Catalina

Do this steps and repeat until allow all you need and stop notifications.Solve for me.

1. On your Mac, choose Apple menu > System Preferences, clickSecurity & Privacy, then click General.
2. Click the lock icon to unlock it, then enter an administratorname and password.
3. Select the sources from which you’ll allow software to beinstalled: There should be a button that says "Allow anyway". If notmake sure you've cancelled the error dialog.

usually you will not be allowed to install the applications dowloaded form other sources .... you need to first give permissions in the system Preferences

1. apple-icon on left top corner > System Preferences > click Security & Privacy > then click General... now Click the lock icon to unlock it ...2.now, you will be shown with below attached image ... click allow anyway ..
2. now retry installing ... you are good to go...

Disabling entire Gate Keeper is definitely not a good idea as it will result running any type of program on your system.

You can add Dart to the white list by running this in terminal:

sudo spctl --add "Path_to_flutter/bin/cache/dart-sdk/bin/dart"

You might require to reboot the system in order to apply the changes.

There are several other binaries other than Dart that may get blocked as well.

You can run GateKeeper script to fix the issue:

https://github.com/AmirKamali/Flutter_GateKeeper_Fix

I have published an article with more information how to fix this:

https://medium.com/@amir.n3t/how-to-fix-flutter-idevice-id-running-errors-in-mac-osx-catalina-7aa1f89f61aa