Went looking through the code myself...!

deleted the only subpatch and the patch opened up again (with stray patch cables).

I guess I'll try to salvage it and export some images as a backup...

did you try the disable loadbang/loadmess? you hold option-shift (or some combination I never remember :) when you open the patch. often one of these is the culprit, as a patch shouldn't actually do anything until there's an event (interaction, loadbang, etc).

If it does open, hunt down some loadbangs and see if there's a stack overflow happening somewhere. Apart from that, I'm not sure where a crash would come from, though probably there are ways...