The solution has arrived!!! In the other bug report 80965, Weihua said:
I also found this problem after installing and removing Gnome3. run vinagre from terminal [west@lp]$LANG=C vinagre The warning message say: the file libgvnc-1.0.so.0 can not be found. This issue can be fixed by reinstalling the package "libgtk-vnc-1.0-0". -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/809281 Title: unable to activate VNC plugin - greyed out To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/vinagre/+bug/809281/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs