Installing Pennylane-qchem (win10) : LD_LIBRARY_PATH Error

I’m installing penny-lane-qchem in a win10 box and am getting a error due to the install script looking for a LINUX type system variable: LD_LIBRARY_PATH.

If there is a fix for this - I’d be grateful.

Here is the relevant part of the error msg:

Collecting pyscf
Using cached
ERROR: Command errored out with exit status 1:
command: ‘c:\users\versaggi\qcousins\scripts\python.exe’ -c ‘import sys, setuptools, tokenize; sys.argv[0] = ‘"
:\Users\versaggi\AppData\Local\Temp\pip-install-nfsspi4r\pyscf\’"’"’;f=getattr(tokenize, ‘"’"‘open’"
ile__, ‘"’"‘exec’"’"’))’ egg_info --egg-base 'C:\Users\versaggi\AppData\Local\Temp\pip-install-nfsspi4r\pyscf\pip-eg
cwd: C:\Users\versaggi\AppData\Local\Temp\pip-install-nfsspi4r\pyscf
Complete output (9 lines):
Traceback (most recent call last):
File “”, line 1, in
File “C:\Users\versaggi\AppData\Local\Temp\pip-install-nfsspi4r\pyscf\”, line 207, in
for x in blas_libraries]
File “C:\Users\versaggi\AppData\Local\Temp\pip-install-nfsspi4r\pyscf\”, line 207, in
for x in blas_libraries]
File “C:\Users\versaggi\AppData\Local\Temp\pip-install-nfsspi4r\pyscf\”, line 148, in search_lib_path
paths = os.environ.get(LD_LIBRARY_PATH, ‘’).split(os.pathsep)
NameError: name ‘LD_LIBRARY_PATH’ is not defined
ERROR: Command errored out with exit status 1: python egg_info Check the logs for full command output.

Hi @ProfVersaggi, welcome and thank you so much for your question! :blush:

It seems, unfortunately, that Windows 10 is not among the supported platforms for pyscf which is a required package for PennyLane-Qchem (further details can be found at this GitHub issue).

Solutions to this problem on Windows 10 could be (including the suggestions from the linked issue):

  • Using the Windows Subsystem for Linux (WSL)
  • Using a virtual machine (VM) that emulates a compatible Linux system
  • Using a Docker container that runs a compatible Linux distribution

Feel free to let us know if we can further help with any of these approaches!

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Hello, sorry if it is a wrong place to ask, but I got similar error with try to install pennylane-qiskit on Windows 8.1. I successfully install after that pennylane-qiskit in VirtualBox with Linux, but it may be not very convenient sometimes. Does it possible and reasonable to suppress installing pyscf with qiskit plugin to have possibility work with qiskit plugin on Windows as well?

Hi @qubeat,

Let me have a go modifying the plugin requirements to avoid the PySCF dependency :slightly_smiling_face:

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@qubeat, this is now fixed and you can install the latest version of pennylane-qiskit using:
pip uninstall pennylane-qiskit -y
pip install git+

Thank you @Tom_Bromley - I just succeed after second try - because my previous efforts with earlier version it also needs an --upgrade option

1 Like