External projector distorts my Keynote preview resolution

How do you do,

I tried searching for a similar problem, but found nothing. So, the thing is this: my MacBook was connected to an external projector without putting it to sleep or turning it off. Because of this every time I now use Keynote and click "Play" to start a preview, a lot of the image is now lost from the right-hand side even when the slide resolution should be 1280 x 720. Almost a fifth of the horizontal information is lost.

What to do?

With best regards,
Grham

ksmith80209 said:

In preferences, go to displays and change the resolution of the projector to best match what is on your screen.

Click to expand...

Thanks for the reply.

I suppose I was not clear enough in describing what I my problem was: the resolution glitch appeared when I was not connected to the projector. So I take it your solution is for changing the resolution when I am still plugged into the projector?

But what I ultimately ended up doing was reinstalling iWork and it now works fine.