If your Windows Explorer view settings have the Preview Pane turned on, you will not be able to save over any existing PDF file you open since the preview will be loaded by Windows which locks the file as read only. Turn off the preview pane and you should be able to resume normal save behavior.
If your Windows Explorer view settings have the Preview Pane turned on, you will not be able to save over any existing PDF file you open since the preview will be loaded by Windows which locks the file as read only. Turn off the preview pane and you should be able to resume normal save behavior.