This was the 1st time I've lost something to TextEdit quitting, an app I use daily. This in 10.3.9
I don't recall the Exact sequence of events -it was late- so bear w/me:

TextEdt suddenly quit when I was messing around w/a 2nd or 3rd TxtEdt window open, and trying to copy an image into one -incorrectly, by selecting the image in a Preview window and trying to copy/paste it (no go), then closing that blank doc.

So invalid commands were made, but nothing too taxing I wouldn't think... MDD w/2GB ram.

Can this happen like that, or should I be looking to do some maintenance (or upgrade) to prevent a repeat?

It's possible that it's a bug in TextEdit, given that it's 10.3.9, it probably hasn't been updated in quite a while, and even with lots of testing, software bugs in infrequent error situations like you initially had sometimes don't get caught.

Has everything else in your system been very stable? If so, it might just be a bug in a weird error handling situation in TextEdit.

Yes, everything has been normal otherwise, so wanted to check here.
Something tells me that way back (pre 10.3.9), a similar thing once happened w/TextEdit to me...

Since TexEdit has no real complex preference settings, you might go to Users/(you)/library/Preferences Drag the file, "com.apple.TextEdit.plist" to the trash. Now relaunch TexEdit and see if you can get it to quit doing the same routine.

Will try that, thanks. But unlikely to be able to accurately retrace my same late-night missteps...