Are you sure the process is completing?
What OS? Where do you see the "no editor"? Is ID patched to 8.0.1?
My fault entirely.
When I tried to load the .idml file into BBEdit, I was using a lnk to an old, thrown-out BBEdit version, and that's what caused it.
I thought the editor had opened the file, but it was just the system saying there was no editor.
Thanks. All fixed.