rsi@ubuntu-rsi-controller:~$ sudo apt-get purge unifi
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages were automatically installed and are no longer required:
  ca-certificates-java default-jre-headless fontconfig-config
  fonts-dejavu-core java-common jsvc libasyncns0 libavahi-client3
  libavahi-common-data libavahi-common3 libboost-filesystem1.54.0
  libboost-program-options1.54.0 libcommons-daemon-java libcups2 libflac8
  libfontconfig1 libgoogle-perftools4 libjpeg-turbo8 libjpeg8 liblcms2-2
  libogg0 libpcrecpp0 libpulse0 libsctp1 libsnappy1 libsndfile1
  libtcmalloc-minimal4 libunwind8 libv8-3.14.5 libvorbis0a libvorbisenc2
  lksctp-tools mongodb-clients mongodb-server openjdk-7-jre-headless
  tzdata-java
Use 'apt-get autoremove' to remove them.
The following packages will be REMOVED:
  unifi*
0 upgraded, 0 newly installed, 1 to remove and 48 not upgraded.
After this operation, 96.7 MB disk space will be freed.
Do you want to continue? [Y/n] y
(Reading database ... 102169 files and directories currently installed.)
Removing unifi (5.6.30-10266) ...
 * Stopping Ubiquiti UniFi Controller unifi                              [ OK ]
 Removing any system startup links for /etc/init.d/unifi ...
   /etc/rc0.d/K08unifi
   /etc/rc1.d/K08unifi
   /etc/rc2.d/S92unifi
   /etc/rc3.d/S92unifi
   /etc/rc4.d/S92unifi
   /etc/rc5.d/S92unifi
   /etc/rc6.d/K08unifi
Purging configuration files for unifi (5.6.30-10266) ...
 Removing any system startup links for /etc/init.d/unifi ...
dpkg: error processing package unifi (--purge):
 subprocess installed post-removal script returned error exit status 128
Processing triggers for ureadahead (0.100.0-16) ...
Errors were encountered while processing:
 unifi
E: Sub-process /usr/bin/dpkg returned an error code (1)