I installed Ubuntu 14.04 x64. When I try to install classicmenu-indicator it says about unresolved dependency python-appindicator When I try to install python-appindicator it tries to install python-appindicator:i386 (Why? How to install 64 bit one?). It requires python:i386. When I try to install python:i386 it requires to remove all python dependent packages including important for me. How to install classicmenu-indicator or python-appindicator at this OS? With best regards. Viktor.
I opened Ubuntu software center, selected Edit -> Software Sources, selected Ubuntu Software tab and changed "Download from" to different server (Now it is the Main server).
And all problems are now fixed.
Also look at How do I fix APT errors "W: Failed to fetch [...] Hash Sum mismatch"?