Android specified for property 'signingConfig.storeFile' does not exist

Go to Build -> Generate Signed APK. Create your key (or choose existing) -> next -> next -> done!

If you want to do it "hard way" you need to specify already created release key into signingConfigs before buildTypes. Something like this:

signingConfigs {
        release {
            storeFile file("/yourkey.jks") //check that the file exists
            storePassword "YourPassword"
            keyAlias "YourAlias"
            keyPassword "YourPassword"
        }
    }

But this is useless somewhat. Because Android Studio provides very simple and easy way to create a signed APK file ready for publishing. And also specifying your key's password into the build.gradle file... - it isn't advisable to do it in terms of security.

My key was in

APPROOT/myKey.jks

Whilst the gradle was looking in

APPROOT/app/myKey.jks

I think you specify that second path on the second dialogue when you generate the signed apk, but I haven't checked it out, can someone confirm?