If a time-consuming operation is in progress the Cancel button will appear at the bottom of the status pane, on the right side of the window. You can cancel the current operation by pressing this button or typing Cmd-. Once you have done so the button will go away and the Status line will read メCancellingノ.モ
Most computers support the cancel command and with these machines it will only take a few seconds. But some machines ignore the command and insist on completing the current operation. In these cases the status line will read メCancellingノモ for quite a while. The only ways to quickly exit from this situation are to close the connection or quit from Fetch.