Gradle project refresh failed after Android Studio update

Check the Gradle home path after the update to version 1.5. It should be ../gradle-2.8.

Most people do not read the comments so to summarize (Thanks to @Industrial-antidepressant and @wrecker):

As suggested in a bug ticket you should try the following:

1. Close Android Studio
2. go to android-studio/plugins/gradle/lib
3. Delete (or better move them somewhere to have a backup) all gradle-*-1.8 files
4. Start Android Studio again and rebuild/refresh.

It should work. Make sure to star the above bug ticket to get informed.

Little tip: Try the new compile setting Settings -> Compiler -> Gradle and activate the third in-process build for a speed up. Depending on your project setting you might want to select the first one as well. With that my project build time reduced to 2-4 seconds (before 20+ seconds).