ImportError: DLL Load Failed: The Specified Procedure Could Not Be Found

When using version 2014 on Windows, you may have problems running QuantumATK or starting calculations in the Job Manager inside QuantumATK, and it shows the following error:

Traceback (most recent call last):
  File "", line 1, in
  File ".\zipdir\NL\__init__.py", line 5, in
  File ".\zipdir\NLEngine.py", line 36, in
  File ".\zipdir\NLEngine.py", line 18, in swig_import_helper
ImportError: DLL load failed: The specified procedure could not be found.

This is caused by having multiple versions of QuantumATK installed at the same time. That’s in principle possible, but exactly in the 2014 version (not 13.8, and not 2015 or later), QuantumATK resolves the DLL location by the PATH environment variable, which means that the 2014.x “bin” directory must come first in the path, before any other QuantumATK bin directory. Since the directory is added last to the path upon installation, the issue typically only occurs if you have 13.8 or an older 2014.x version installed. The easiest solution is therefore to uninstall all older versions, or at least remove them from your PATH, then all should work fine. If you want to keep 13.8 (you really should not keep 2014.2 if you install 2014.3), you must ensure the 2014 version “bin” directory comes before the 13.8 bin directory in the PATH. If you have access to 2015 or later, you might as well uninstall both 13.8 and 2014 and just use the newer version! For instructions on editing the PATH on Windows, see e.g. here.