Why is so difficult to insert or remove the filter from the portafilter on my Dedica unit?

Rather than trying to force the filter in with your hands or fingers, place the filter basket upside down on the counter (use a towel underneath the filter to avoid scratching the counter surface), and then with the portafilter face down, align it with the filter basket and press down gently with your body weight until it snaps into place.

To remove it from the portafilter watch this short video