No matter how slight a change I make, I cannot save a pdf file without giving it a new name
Seems like a standard config that most people use. There's probably something else on your system setup that is causing this.
Couple of things to try - if you aren't on 10.1.3, use help->check for updates to get there
If you are already on 10.1.3, run a repair on Acrobat installation from the control panel/add remove programs panel
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