I have 2 solid objects, and a boolean subtract (tried with union too) does not work. The circular object has a tiny gap since I created it flat then deformed it, but that should not be the problem I guess.
after clicking 'done', it says "calculating" for a few seconds, then returns to the default state, but no boolean operation has been performed.

any thoughts?

oops, the file is too big, 69 Mb, can't make it any smaller.