I have been working on a project for over six months now when after an Android Studio upgrade, some of my files open with the error "File was loaded in wrong encoding: UTF-8".
POSSIBLE DUPLICATE:
In my case Android Studio does not show the wrong file contents, as in text from another file or from somewhere else, it shows the wrong encoding. I found a bug on the Google Issue Tracker that explains my problem. Google Issue. Have a look at the images attached to the bug for a clear explanation.