My first project using 4.0.
At one point, I had a huge panic because I saved the project right while my computer was shutting down, and then got the “Missing DNA block” error, but fortunately I had a backup to save the day 😌
I have now downloaded the free powersave addon so that doesn’t happen again.
DNA is like a directory of what is in a blend file and where in it it is. Blend files are more or less just a dump of blenders internal state, ingenious if you ask me.