You can close the program via the menu Exit/Close PC CADDIE. You can also click on the „x“ from the top-right corner of the window.
The program asks once more if you want to make a intranet data synchronization before closing.
Press Yes if you have data to upload, No when you don't want to upload anything, and Cancel if you want to keep the program opened.
Pressing Return/Enter on the keyboard means Yes.