Issues running apsimNGpy on Windows

[spencercole6-ops]

Hi Dr. Magala,

I am new to the APSIM scene and have been running into several issues trying to run apsimNGpy on Windows. I am hoping you may be able to help me troubleshoot the issues I am encountering. So far I have not had any issues running the APSIM model itself from the GUI, just problems interfacing with the python package. I've tried two main methods for getting apsimNGpy to work with different results and errors as I'll explain below.

Part 1:

First, I retained the more recent version of APSIM (v2025.11.7929.0) that I had been running through the GUI and tried to run apsimNGpy. I manage my python packages through conda but since apsimNGpy is not available through conda channels I installed it via git in the command line using pip install git+https://github.com/MAGALA-RICHARD/apsimNGpy.git. After installing, I tried loading and running an example wheat model using the following:

from apsimNGpy.core.apsim import ApsimModel import pandas as pd import numpy as np wheat_example_path = "C:/Users/user/Downloads/Examples/Wheat.apsimx" model = ApsimModel(model=wheat_example_path) model.run(report_name='Report', verbose=True) results = model.results

And the model ran without issue and I was able to view the results. However, when I started trying to modify or inspect the model following your tutorial pages online I started receiving an error. I tried several commands, including model.inspect_model('Models.Manager', fullpath=True) and each time I got an error stating AttributeError: 'Simulations' object has no attribute 'FindAllDescendants'. This error seemed to occur when I tried doing anything other than loading and running the model. Unfortunately, because of the issue I'll explain in part 2 below I cannot currently reproduce the full traceback for the errors. If I recall correctly when troubleshooting I had also tried using an earlier release apsimNGpy but that didn't solve the issue either.

Part 2:

Through trying to determine what was going on with my errors in part 1 I read that there were recent changes to the structure of APSIM that could interface poorly with apsimNGpy and had the idea of reverting to an earlier APSIM version (v2025.08.7842.0 - I saw in another discussion with here a Mac user that this version passed all tests) to see if that might solve the issue. I uninstalled my previous APSIM model and reinstalled the older version. Then upon trying to run from apsimNGpy.core.apsim import ApsimModel I received a new error NameError: name 'WindowsPath' is not defined. Here is the full traceback:

from apsimNGpy.core.apsim import ApsimModel
NameError Traceback (most recent call last)
Cell In[1], line 1
----> 1 from apsimNGpy.core.apsim import ApsimModel

File ~\miniconda3\Lib\site-packages\apsimNGpy_init_.py:1
----> 1 from apsimNGpy.core.config import set_apsim_bin_path, get_apsim_bin_path, locate_model_bin_path
3 all = [set_apsim_bin_path, get_apsim_bin_path, locate_model_bin_path]
5 CURRENT_BIN = get_apsim_bin_path()

File ~\miniconda3\Lib\site-packages\apsimNGpy\core\config.py:379
373 logger.info(f"APSIM binary path set to '{validated_bin}'.")
375 return True
378 @cache
--> 379 def apsim_version(bin_path=get_apsim_bin_path(), release_number: bool = False, verbose: bool = False):
380 """
381 Display version information of the APSIM model currently
382 in the apsimNGpy config environment. runs externally through subprocess module
(...) 399 '2025.8.7844.0'
400 """
401 try:

File ~\miniconda3\Lib\site-packages\apsimNGpy\core\config.py:270, in get_apsim_bin_path()
267 pass # we are not interested in raising at this point
268 return apsim_bin_path
--> 270 return _get_bin()

File ~\miniconda3\Lib\site-packages\apsimNGpy\core\config.py:260, in get_apsim_bin_path.._get_bin()
258 if not exists(apsim_bin_path):
259 auto_path = auto_detect_apsim_bin_path()
--> 260 create_config(CONFIG_PATH, apsim_path=auto_path)
261 return auto_path
262 if apsim_bin_path:
263 # make sure it has the required binaries

File ~\miniconda3\Lib\site-packages\apsimNGpy\settings.py:23, in create_config(config_path, apsim_path)
22 def create_config(config_path, apsim_path=""):
---> 23 _CONFIG = create_bin_paths_used(config_path, apsim_path)
24 _CONFIG['Paths'] = {'APSIM_LOCATION': apsim_path}
25 with open(config_path, 'w') as configured_file:

File ~\miniconda3\Lib\site-packages\apsimNGpy\settings.py:36, in create_bin_paths_used(config_path, apsim_path)
34 pp = _CONFIG['PreviousPaths']
35 prev = pp.get('BINS', "[]")
---> 36 binS = set(eval(prev))
37 BINS = [i for i in binS if os.path.exists(i)]
38 BINS = list(dict.fromkeys(BINS))

File :1

NameError: name 'WindowsPath' is not defined

I then tried to revert back to the newer version of APSIM again to deal with my initial error and upon doing so I am continuing to encounter this one (NameError: name 'WindowsPath' is not defined). If you can share any thoughts you might have on how I might solve these issues I would really appreciate it!

Thank you very much,
Spencer

[MAGALA-RICHARD]

Hello Spencer,
I guess your env is now polluted with something untraceable. Return to the older version of APSIM and try the code below. Please replace apsim_bin_path with a real path pointing to your installed APSIM binaries; meanwhile, I will try to check the bot error logs to synchronize apsimNGpy with the latest APSIM version

from apsimNGpy.core.config import apsim_bin_context
with apsim_bin_context(apsim_bin_path=r'APSIM2025.8.7844.0/bin'):
   # now import apsimNGpy model
   from apsimNGpy.core.apsim import ApsimModel
# after importing, you can exit the with block
model = ApsimModel('Wheat')# loading default files is easy by specifying just the plant or file name, without .apsimx extension,
model.run()
model.results

[spencercole6-ops]

Hi Dr. Magala,

Thanks so much for the prompt reply! Before reverting to an older APSIM version I just wanted to check that first line since I haven't been able to import anything related to apsimNGpy on any version since I apparently polluted my env. Just from trying that first line of code from apsimNGpy.core.config import apsim_bin_context I am still getting that Windows path error. Below is the full traceback. I am not very experienced with manually editing and tracking Windows path variables since most of the packages I've worked with have automatically added them, but do you think I need to modify my path outside of python first? Could my issues be related to the fact that my python packages are managed through conda? I'm hoping to get past this first "WindowsPath is not defined" error before reverting APSIM versions since I have some model files I need to do testing on that aren't compatible with the older version.

from apsimNGpy.core.config import apsim_bin_context

NameError Traceback (most recent call last)
Cell In[1], line 1
----> 1 from apsimNGpy.core.config import apsim_bin_context

File ~\miniconda3\Lib\site-packages\apsimNGpy_init_.py:1
----> 1 from apsimNGpy.core.config import set_apsim_bin_path, get_apsim_bin_path, locate_model_bin_path
3 all = [set_apsim_bin_path, get_apsim_bin_path, locate_model_bin_path]
5 CURRENT_BIN = get_apsim_bin_path()

File ~\miniconda3\Lib\site-packages\apsimNGpy\core\config.py:379
373 logger.info(f"APSIM binary path set to '{validated_bin}'.")
375 return True
378 @cache
--> 379 def apsim_version(bin_path=get_apsim_bin_path(), release_number: bool = False, verbose: bool = False):
380 """
381 Display version information of the APSIM model currently
382 in the apsimNGpy config environment. runs externally through subprocess module
(...) 399 '2025.8.7844.0'
400 """
401 try:

File ~\miniconda3\Lib\site-packages\apsimNGpy\core\config.py:270, in get_apsim_bin_path()
267 pass # we are not interested in raising at this point
268 return apsim_bin_path
--> 270 return _get_bin()

File ~\miniconda3\Lib\site-packages\apsimNGpy\core\config.py:260, in get_apsim_bin_path.._get_bin()
258 if not exists(apsim_bin_path):
259 auto_path = auto_detect_apsim_bin_path()
--> 260 create_config(CONFIG_PATH, apsim_path=auto_path)
261 return auto_path
262 if apsim_bin_path:
263 # make sure it has the required binaries

File ~\miniconda3\Lib\site-packages\apsimNGpy\settings.py:23, in create_config(config_path, apsim_path)
22 def create_config(config_path, apsim_path=""):
---> 23 _CONFIG = create_bin_paths_used(config_path, apsim_path)
24 _CONFIG['Paths'] = {'APSIM_LOCATION': apsim_path}
25 with open(config_path, 'w') as configured_file:

File ~\miniconda3\Lib\site-packages\apsimNGpy\settings.py:36, in create_bin_paths_used(config_path, apsim_path)
34 pp = _CONFIG['PreviousPaths']
35 prev = pp.get('BINS', "[]")
---> 36 binS = set(eval(prev))
37 BINS = [i for i in binS if os.path.exists(i)]
38 BINS = list(dict.fromkeys(BINS))

File :1

NameError: name 'WindowsPath' is not defined

[MAGALA-RICHARD]

Does this occur while you are running older APSIM versions; if yes I have tried to fix the file structure bugs with the newer version: you may try it out via GitHub. Let me investigate this NameError shortly

…

On Fri, Dec 5, 2025 at 12:36 PM spencercole6-ops ***@***.***> wrote: Hi Dr. Magala, Thanks so much for the prompt reply! Before reverting to an older APSIM version I just wanted to check that first line since I haven't been able to import anything related to apsimNGpy on any version since I apparently polluted my env. Just from trying that first line of code from apsimNGpy.core.config import apsim_bin_context I am still getting that Windows path error. Below is the full traceback. I am not very experienced with manually editing and tracking Windows path variables since most of the packages I've worked with have automatically added them, but do you think I need to modify my path outside of python first? Could my issues be related to the fact that my python packages are managed through conda? I'm hoping to get past this error before reverting APSIM versions since I have some model files I need to do testing on that aren't compatible with the older version. from apsimNGpy.core.config import apsim_bin_context NameError Traceback (most recent call last) Cell In[1], line 1 ----> 1 from apsimNGpy.core.config import apsim_bin_context File ~\miniconda3\Lib\site-packages\apsimNGpy_*init*_.py:1 ----> 1 from apsimNGpy.core.config import set_apsim_bin_path, get_apsim_bin_path, locate_model_bin_path 3 *all* = [set_apsim_bin_path, get_apsim_bin_path, locate_model_bin_path] 5 CURRENT_BIN = get_apsim_bin_path() File ~\miniconda3\Lib\site-packages\apsimNGpy\core\config.py:379 373 logger.info(f"APSIM binary path set to '{validated_bin}'.") 375 return True 378 @cache --> 379 def apsim_version(bin_path=get_apsim_bin_path(), release_number: bool = False, verbose: bool = False): 380 """ 381 Display version information of the APSIM model currently 382 in the apsimNGpy config environment. runs externally through subprocess module (...) 399 '2025.8.7844.0' 400 """ 401 try: File ~\miniconda3\Lib\site-packages\apsimNGpy\core\config.py:270, in get_apsim_bin_path() 267 pass # we are not interested in raising at this point 268 return apsim_bin_path --> 270 return _get_bin() File ~\miniconda3\Lib\site-packages\apsimNGpy\core\config.py:260, in get_apsim_bin_path.._get_bin() 258 if not exists(apsim_bin_path): 259 auto_path = auto_detect_apsim_bin_path() --> 260 create_config(CONFIG_PATH, apsim_path=auto_path) 261 return auto_path 262 if apsim_bin_path: 263 # make sure it has the required binaries File ~\miniconda3\Lib\site-packages\apsimNGpy\settings.py:23, in create_config(config_path, apsim_path) 22 def create_config(config_path, apsim_path=""): ---> 23 _CONFIG = create_bin_paths_used(config_path, apsim_path) 24 _CONFIG['Paths'] = {'APSIM_LOCATION': apsim_path} 25 with open(config_path, 'w') as configured_file: File ~\miniconda3\Lib\site-packages\apsimNGpy\settings.py:36, in create_bin_paths_used(config_path, apsim_path) 34 pp = _CONFIG['PreviousPaths'] 35 prev = pp.get('BINS', "[]") ---> 36 binS = set(eval(prev)) 37 BINS = [i for i in binS if os.path.exists(i)] 38 BINS = list(dict.fromkeys(BINS)) File :1 NameError: name 'WindowsPath' is not defined — Reply to this email directly, view it on GitHub <#35 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AZHIYYDMKMMXVBNRKMVDOL34AHGEXAVCNFSM6AAAAACOC2NYC6VHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTKMJXGU3DMMQ> . You are receiving this because you commented.Message ID: ***@***.*** com>

[spencercole6-ops]

When I initially tried with the newer APSIM version I was able to run the models but was getting that other error when trying to edit things (AttributeError: 'Simulations' object has no attribute 'FindAllDescendants'). So originally I didn't get the path error, but I attempted to revert to an older APSIM version and started getting this new path error. After returning to the newer APSIM version I still get the path error when trying to load anything related to apsimNGpy.

I'll try reinstalling my apsimNGpy to get the new version now.

Thank you!

[MAGALA-RICHARD]

Is there an alternative of pip cache purge with anaconda, it always clear env caches for me.

…

On Fri, Dec 5, 2025 at 1:47 PM spencercole6-ops ***@***.***> wrote: When I initially tried with the newer APSIM version I was able to run the models but was getting that other error when trying to edit things (AttributeError: 'Simulations' object has no attribute 'FindAllDescendants'). So originally I didn't get the path error, but I attempted to revert to an older APSIM version and started getting this new path error. After returning to the newer APSIM version I still get the path error when trying to load anything related to apsimNGpy. I'll try reinstalling my apsimNGpy to get the new version now. Thank you! — Reply to this email directly, view it on GitHub <#35 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AZHIYYHOUL5YBFGTQWZRNK34AHONTAVCNFSM6AAAAACOC2NYC6VHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTKMJXGYYDINY> . You are receiving this because you commented.Message ID: ***@***.*** com>

[spencercole6-ops]

I tried using a fresh install of apsimNGpy and received the same path error. There is a cache purge alternative for conda, conda clean which I just tried. Didn't seem to fix my issue.

[MAGALA-RICHARD]

Can you please share your folder structure where you are running the software

…

On Fri, Dec 5, 2025 at 2:04 PM spencercole6-ops ***@***.***> wrote: I tried using a fresh install of apsimNGpy and received the same path error. There is a cache purge alternative for conda, conda clean which I just tried. Didn't seem to fix my issue. — Reply to this email directly, view it on GitHub <#35 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AZHIYYEW2OK5WZ65VNMIPBT4AHQOXAVCNFSM6AAAAACOC2NYC6VHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTKMJXGYYTIOA> . You are receiving this because you commented.Message ID: ***@***.*** com>

[spencercole6-ops]

Do you mean where my apsimNGpy package is located?

My apsimNGpy package is located here: C:\Users\spenc\miniconda3\Lib\site-packages\apsimNGpy
My actual APSIM model is located here: C:\Program Files\APSIM2025.11.7937.0

I also made sure to manually add C:\Program Files\APSIM2025.11.7937.0\bin to my environment variables path but that did not solve my issue either.

[MAGALA-RICHARD]

Try to create a new virtual environment away from your current working directory

…

On Fri, Dec 5, 2025 at 2:21 PM spencercole6-ops ***@***.***> wrote: Do you mean where my apsimNGpy package is located? My apsimNGpy package is located here: C:\Users\spenc\miniconda3\Lib\site-packages\apsimNGpy My actual APSIM model is located here: C:\Program Files\APSIM2025.11.7937.0 I also made sure to manually add C:\Program Files\APSIM2025.11.7937.0\bin to my environment variables path but that did not solve my issue either. — Reply to this email directly, view it on GitHub <#35 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AZHIYYG77N2UQOA2GHCJUE34AHSN7AVCNFSM6AAAAACOC2NYC6VHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTKMJXGYZDONA> . You are receiving this because you commented.Message ID: ***@***.*** com>

[MAGALA-RICHARD]

After reviewing your traceback carefully, here’s what I recommend:

1. Locate the APSIM configuration file:

from apsimNGpy.settings import CONFIG_PATH
import os
os.startfile(CONFIG_PATH)

2. Once opened, find the [PreviousPaths] section.

3. Delete all paths listed under this section, then save and close the file.

This will clear any outdated APSIM paths that may be causing the issue.

[spencercole6-ops]

Wow fantastic! I tried your suggestion above of removing PreviousPaths from the CONFIG_PATH file and that seemed to solve both issues. I believe they were pointing to previous versions. I'm not getting the WindowsPath error and from some brief testing it seems that I am not receiving the AttributeError: 'Simulations' object has no attribute 'FindAllDescendants' either. I was now able to run model.inspect_model('Models.Manager', fullpath=True) and the get_weather_from_web() function.

Thanks very much for your help troubleshooting this!

[MAGALA-RICHARD]

“You’re welcome. I’ll now convert this into an issue so that if others run into the same problem, they’ll know how to resolve it.”

[spencercole6-ops]

Thanks! From a little more testing I have been able to run the model and pull weather data, although when trying to load our own .met file in using model.replace_met_file I am getting another error that again seems to be related to the code checking versions. The error mentions that model.replace_weather_file is depreciated... Is there another method I should use for loading these files? Thanks again and sorry for the trouble. Here's my traceback.

model.replace_met_file(weather_file="path/to/met/file")
C:\Users\spenc\AppData\Local\Temp\ipykernel_18776\692839245.py:1: DeprecationWarning: replace_met_file() is deprecated and will be removed in a future release. Prefer newer weather-configuration helpers or set Weather.FileName directly.
model.replace_met_file(weather_file="path/to/met/file")

NameError Traceback (most recent call last)
Cell In[18], line 1
----> 1 model.replace_met_file(weather_file="path/to/met/file")

File ~\miniconda3\Lib\site-packages\apsimNGpy\core\core.py:3377, in CoreModel.replace_met_file(self, weather_file, simulations, exclude, **kwargs)
3375 sims = (i for i in simus if i.Name not in exclude)
3376 for sim in sims:
-> 3377 if APSIM_VERSION_NO > BASE_RELEASE_NO or APSIM_VERSION_NO == GITHUB_RELEASE_NO:
3378 weathers = ModelTools.find_all_in_scope(sim, Models.Climate.Weather)
3379 else:

NameError: name 'APSIM_VERSION_NO' is not defined

[MAGALA-RICHARD]

Yes absolutely. Please see the example below:

model =ApsimModel('Maize')
model.edit_model(model_type='Models.Climate.Weather', model_name='Weather', met_file='yourfile.met')

[spencercole6-ops]

Great that works, thank you!

[MAGALA-RICHARD]

You're welcome!

…

On Mon, Dec 8, 2025 at 1:40 PM spencercole6-ops ***@***.***> wrote: Great that works, thank you! — Reply to this email directly, view it on GitHub <#35 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AZHIYYBY2WA3LHUOTFYWTCL4AXH4DAVCNFSM6AAAAACOC2NYC6VHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTKMRQGE3DANI> . You are receiving this because you commented.Message ID: ***@***.*** com>