When I edit and then try to save a .pdf, I get an error: "Could not save (file name) because the file is already in use or left open." But it is not open or in use elsewhere. (And, no, the preview pane in Windows Explorer is not open.) I end up having to "Save as" with a new file name, but then I end up with multiple copies of my document, and often, I can't delete the old ones.
How about if you save the file by using the keyboard shortcut,do you still experience the same?