what kmitchell.12catblackstudio... has said is true most of the time
I have test my own version by forcing a crash (today)
you should have this pop up when restarting again, see picture.
the most important step is to 'ok' it
other wise all is lost!
it give you the chance to rename the file
if all is to your liking
now the next important step
come out of the programme
clean up your system on your machine
reboot it again
recall your work again
it should be 'ok' this time round
say after every 10 mins do a save
check this by doing an tab to tab
on your file explorer
happy designing
from Alan