Couldn't load OCC geometry

I am using NETGEN-6.2-dev. I am running python scripts to import .step files and mesh geometry. All was working fine. Suddenly from one run to the next I started getting this error:

Developed by Joachim Schoeberl at
2010-xxxx Vienna University of Technology
2006-2010 RWTH Aachen University
1996-2006 Johannes Kepler University Linz
Including OpenCascade geometry kernel
optfile ./ng.opt does not exist - using default values
togl-version : 2
OCC module loaded
loading ngsolve library
Using Lapack
Including sparse direct solver Pardiso
Including sparse direct solver UMFPACK
Running parallel using 6 thread(s)
importing NGSolve-6.2.2002
(should) load python file ‘C:/00_Temp/’
Traceback (most recent call last):
File “”, line 4, in
netgen.libngpy._meshing.NgException: Couldn’t load OCC geometry
Finished executing C:/00_Temp/

The code is:

from netgen.occ import *
from ngsolve import *

geo = OCCGeometry('C:/Temp/dome.step') #import step file

I have tried rebooting and re-installing ngsolve/netgen, but get the same error.

Any suggestions for what might have gone wrong or how to fix?

Update: not sure why this fixed the problem, but I moved the step file to a different folder, updated the path in my script and it worked.