I've just launched Kubuntu 16.04 from the live USB disk, and found that none of my media (MP4s, MP3s) would play, using either Amarok or Dragon Player. I understand this is because of the lack of non-free codecs, but new users may now be aware of this - see for example #360921. Please display an error instead of simply failing to play without any sort of feedback to the user. Given the wide choice of distros that do play media out of the box, a new user who's evaluating KDE is likely to just give up on it. Reproducible: Always
I meant that casual users are probably *not* aware of the legal status of MP3 codecs.
Please report this to the distribution, they should use the existing options to suggest the installation of the missing codecs.