$ dpkg -l x2gobroker-daemon

...

ii  x2gobroker-daemon                             0.0.0.5-0~x2go1                               X2Go http(s) based session broker (daemon)

(Reading database ... 58838 files and directories currently installed.)

Preparing to replace x2gobroker-daemon 0.0.0.5-0~x2go1 (using x2gobroker-daemon_0.0.0.5-0~x2go1_all.deb) ...

 * Stopping X2Go Session Broker standalone daemon x2gobroker                                                                                                                                          [ OK ] 

Unpacking replacement x2gobroker-daemon ...

Setting up x2gobroker-daemon (0.0.0.5-0~x2go1) ...

Group x2gobroker already exists.

User x2gobroker already exists.

dpkg: error processing x2gobroker-daemon (--install):

 subprocess installed post-installation script returned error exit status 1

Processing triggers for ureadahead ...

Errors were encountered while processing:

 x2gobroker-daemon

If I do a purge of the x2gobroker-daemon package and then install it, it installs fine.