Could not locate particle after crossing a lattice boundary

Hello everyone,

I am facing a problem in running a geometry modeled in openMC version 0.7.1 into openMC version 0.7.0. It works perfectly in v 0.7.1 but gives error that “Could not locate particle after crossing lattice boundary” when executed in v 0.7.0.

My question is, what change i have to make in geometry file when using v 0.7.0. The only difference i know is that while making a cell instead of “region”, “surface” term is used.

Regards,
ALI