I've been using 14.04 LTS for the last few weeks and have just updated to 15.10 CMUS had been working fine on 14.04, but ever since I upgraded, it just doesn't work.
I've installed and removed cmus several times, but I can't get it to start.
One of the cmus dependencies starts a network server that causes cmus to hang while it never loads. The following resolves the issue:
$ apt-get purge libdnet dnet-common
You can perform a fresh cmus install without the server as so:
$ sudo apt-get --no-install-recommends install cmus cmus-plugin-ffmpeg
Here is the related bug report.