I'm sorry you're experiencing this.
This sounds like a bug (in sage-mode) that I fixed a while ago in which it would get stuck waiting for the prompt. What version of sage-mode
are you using? C-h v sage-mode-version RET
. The latest released version is 0.10
and doesn't have such a bug to the best of my knowledge. If you are using an older version please upgrade. Otherwise I would really appreciate a bug report at https://bitbucket.org/gvol/sage-mode/issues?status=new&status=open so that I don't forget it.
Also, what version of Sage are you using, and do you have anything in your ~/.sage/init.sage
?