stl and obj import export python broken Here's the problem: Whenever I try to import or export anything(.stl and .obj), I get the following error:


  Traceback (most recent call last):
  File
  "C:\Users\owlteagames\Downloads\blender-2.78-windows64\2.78\scripts\addons\io_mesh_stl__init__.py",
  line 203, in execute
      from . import stl_utils
  File "C:\Users\owlteagames\Downloads\blender-2.78-windows64\2.78\scripts\addons\io_mesh_stl\stl_utils.py",
  line 31, in 
      import contextlib
  File "C:\Users\owlteagames\Downloads\blender-2.78-windows64\2.78\python\lib\contextlib.py",
  line 4, in 
      from collections import deque
  File "C:\Users\owlteagames\Downloads\blender-2.78-windows64\2.78\python\lib\collections__init__.py",
  line 10, in 
      from operator import itemgetter as _itemgetter, eq as _eq
  File "C:\Users\owlteagames\AppData\Roaming\Blender
  Foundation\Blender\2.78\scripts\addons\operator.py", line 5, in
  
      from .hmd import HMD 
  SystemError: Parent module '' not loaded, cannot perform relative import


I don't really know what any of this means, but I've noticed...that the problem seems to be centered around a bunch of different Python scripts.

I have been researching this for three days without any luck. My boss is about to fire me for "Claiming I Know How To Use Blender When I Obviously Don't." I've uninstalled and reinstalled Blender, and no help. I'm afraid that if I roll back to an earlier Blender version, that all my files opened in the new Blender will be incompatible! 

I even tried going into the preferences under files paths, to see if the lack of connections to everything was the culprit- the boxes next to FONT, TEXTURES, RENDER OUTPUTS, etc were all empty except for the TEMP path. I hooked up what I could- fonts, scripts, but the same error appears- completely unaffected by my path connections effort.

Many Thanks to the person able to help, and thank you for reading this even if you can't help! Let's save my job! Haaa...
thank you metaphor_set and sambler!

a combination all of your suggestions helped. I had tried to download a theme, and I guess it didn't want to work right. Anyhow, I deleted my pycache, restarted, and made sure to select Selection Only on export, and change the type from Batch to Object. After that, things started working again. 

thanks again! I hope this helps somebody else!