12d Model

I'm using an interface polygon to surround the areas where I am calculating volumes. I get the message: "Bad polygon: Polygon intersects itself!" Does anyone have an idea how to fix.

I'm a new user.....probably something in my workflow.

Yes, I tried opening it, no luck.......but after a bit of a wait the lock was removed. There seems to be a time limit but I'm not sure exactly how long it is.

Thanks for the reply.

My computer crashed while in a 12d project. When I go back to the project after restarting, the project folder is locked. Is there anyway to override this lock or is there a time limit on the lockout?