Can't Copy to Clipboard from Vim

I believe your copy problem is caused by:

mouse=a 

in your .vimrc This sets your vim into visual mode whenever you select something with the mouse. And for some mad reason one is not allowed to copy when in visual mode. You can get around it by holding down shift when selecting text not to go into visual mode allowing you to use the copy menu.

or you could change to:

:set mouse=v

and copy will work again. add it to your ~/.vimrc file if you want it to be permanent

sudo apt-get install vim-gtk will likely solve this problem for other Googlers.

Good ol' terminal-style vim doesn't have access to the clipboard, which is a part of the X windows system. Installing vim-gtk gives vim the access that it needs to modify and view the clipboard.