4.11 broke my game

I have this too and its annoying. I did backup,but using whatever version is on the hdd, what is going to prevent this error ?

What causes it ?

I get the renaming thing, but thats a hack and I don’t like it much for a supposedly professional engine.

is there a readme I missed, aiding in the avoidance of such errors ?

Btw, my upgrade was simply from 4.10 to 4.11, hardly a huge step.

Thx