keynote
The following warning appears:
This happens both when I save and the autosave (which happens often). It is a modal box and interrupts workflow.
No other applications are running, and the issue survives program and operating system restarts. What could be causing this?
(This issue is new with Mavericks / Keynote '13).
You cannot (if you want to be sure of it, simply search for “note” in Keynote’s help).
Comments are explicitly made for the presenter, not the audience. They behave just like Presenter Notes, except they are positioned on the slides instead of being meta-data.
If you want to show post-it notes on the screen, you'll have to obtain a post-it image somewhere, and then fill it with text.
The easiest way to do so is to take a screen capture of a dashboard widget. I'll be nice, here it is for you ;)
You can then simply add it as background image of a rectangle, and fill it with text however you please.
I don't have a complete answer, but I have seen this as well - as long as Keynote 6.x is installed, I can't set the Open with... to Keynote 5. I've been deleting Keynote 6 from Finder, but unfortunately it comes back every time a Software Update is performed, so it's only a partial solution.
Best Answer
The file might be being modified by another process. You can see as the file is accessed by various processes by running:
Use the file normally, then attempt to save. If you get the error, check back in Terminal to see if any other processes have accessed the file.