@PeterJones: Again, thanks very much for your quick and thorough response! Of course, without the exact sequence of events and messages, it’s impossible to reproduce the problem. Usually basic operations liking open, close, save don’t cause problems, so I was not in the kind of frame of mind in which I was carefully recording everything I did and everything the app did. Still it is weird that, when I shut down Notepad++ and started it up a second time, my changes were there, but when I shut it down and started it up a third time, they were gone. I looked in the backup location and the recycle bin, but no luck. Only ways that could happen that I can think of: either I removed the changes myself in Notepad++ (which I didn’t), or I accidentally deleted the file (which would have put it into the recycle bin). Have to just chalk it up to a glitch of some kind.