I often get the error message "Check Out required" when trying to open sdlxliff files with the quick merge function in Studio 2014, which makes it very hard to work with files in large numbers. One of my clients rarely sends packages, but sdlxliff files which I then import into an existing project. And usually I can open them one by one in the editor, but when using the quick merge function, the Check Out Error almost always appear (when handling files from this Client).

Just now, it happened with a regular package though, created in Studio 2017.

It's obviously not a question about the File Type Identifier since this happens exclusively with sdlxliff files.