Comment 11 for bug 237325

@Leroy: The thing about composing e-mail in Evolution is, as far as I can see, completely unrelated--try looking at other bug reports or forum posts to see if anyone else has experienced that.

Anything that would normally use gksudo--including the upgrade manager and synaptic being launched the normal way, will not work. You should still be able to run any of them (as a work-around) by using a command line and doing "sudo whatever", e.g. "sudo synaptic", "sudo update-manager".

"apt-get update", like any command that affects the system for all users, will need "sudo" before it. If "sudo apt-get update" isn't working, then that would be another problem...