Thanks to you both. Yes I was in grid, but I certainly didn't have the whole folder highlighted when I made that particular caption change, which suddenly seemed to apply itself through the entire library, in any other folder that I opened as well. I was preparing to make the said installation of the back-up, when I figured that perhaps I could just shut down lightroom first and see if it all came back to normal on its own. Prior to this, for some unknown and illogical reason, I went into a completely different folder, highlighted all the photos (which originally had different captions and would normally read <mixed> when you do this), the caption box went blank, and a few seconds later, just filled itself up again with the right, original captions. So the problem sorted itself out for no logical reason and I didn't have to resort to the old backup. A little quirk that fortunately righted itself. The lesson I learned is perhaps to type more slowly when doing captions - sometimes my fingers get ahead of me. Also, when doing several photos with the same caption, and thus several are highlighted in the grid, after writing the caption I now click back onto one of those photos (kind of confirming the caption), before moving on to another group. This seems to have helped it not happening again. Thanks so much!
