Today I upgraded to Ubuntu 15.10, no errors happened during the upgrade but after the upgrade I can log in using my username and password but unity does not work. No launcher, no panel absolutely nothing just the background.
I tried to start unity myself using compiz --replace unity
it gives me an error about a missing function definition in libunity.so
and it fails to load.
Please can you help me with this?
[UPDATE]
output of sudo apt-cache policy libunity9
is
libunity9:
Installed: 7.1.4+15.10.20151002-0ubuntu1
Candidate: 7.1.4+15.10.20151002-0ubuntu1
Version table:
*** 7.1.4+15.10.20151002-0ubuntu1 0
500 http://sy.archive.ubuntu.com/ubuntu/ wily/main amd64 Packages
100 /var/lib/dpkg/status
[UPDATE]
After trying to follow the two answers the error message has changed as follows
DISPLAY=:0 compiz --replace unity
outputs to standard error
compiz (core) - Info: Loading plugin: core
compiz (core) - Info: Starting plugin: core
Invalid MIT-MAGIC-COOKIE-1 keycompiz (core) - Fatal: Couldn't open display :0
compiz (core) - Info: Stopping plugin: core
compiz (core) - Info: Unloading plugin: core