- Create a directory which contains one readonly mp3 file.
- Start Mp3tag.
- Paste the full path of the directory to the field "Verzeichnis" and hit Enter.
- Right-click the mp3 file and select "Tag entfernen".
The file content is changed (tag is removed), the readonly attribute is removed.
Readonly files should not be simply changed without notifying the user. The intention of a readonly flag is to prevent an application from changing the file content. All other applciations that I know tell the user something like "File is readonly and cannot be overwritten". At least, the user should be asked if readonly files should really be overwritten.