I did do the workaround. Still no progress. It says list not initialized. I do not have the complete error message right now. I substitute file.dirrootexternal for file.internal and works without a problem. The list is initialized.
Before we start: External storage means a real sd card or a connected mass storage USB device. This class can also be used to access the secondary storage (File.DirRootExternal). This becomes relevant with newer versions of Android that restrict direct access. It has nothing to do with runtime...