I have received numerous "xlights stopped working"--the popup where windows offers to find a solution to your problem and you have to close the program. I have been doing various things tonight that resulted in this error(saving, rendering, enlarging the time steps, etc). One thing I found (that I will just try to avoid...) is that, when I save my sequence files, I usually drop my preview window back in its normal place (I use a laptop with a single screen, so I need to move the preview window around a lot) just before I save. I found tonight that I get this error message consistently when I do this, but not when I "just save" the sequence without placing the preview screen in its normal place. As I said above, I'll just try to avoid that particular sequence of steps when saving....
3/27 update--it seems like I am getting these "program closed" errors whenever I re-size one of my sequence screen windows then try to save the file. I just tested this by just using the effects screen in its normal place (to the left, stacked with my other default param's...) and I was able to save some effect changes that I did a few minutes ago, which made the program stop with the error message. I also tested it by leaving the re-sized house preview screen superimposed on the sequencer screen; that worked fine. I then resized the preview screen and put it back in its regular place and tried to save--got the close & the error message again.