# Issues possibly related to PyPI metapackage installation (without conda) **URL:** \ **Category:** CADET Troubleshooting\ **Created:** [March 9, 2026, 8:45am UTC](https://forum.cadet-web.de/t/issues-possibly-related-to-pypi-metapackage-installation-without-conda/1408 "2026-03-09T08:45:35Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![ucbevng](https://forum.cadet-web.de/letter_avatar_proxy/v4/letter/u/6f9a4e/32.png) [@ucbevng](https://forum.cadet-web.de/u/ucbevng)\ **Post date:** [March 9, 2026, 8:45am UTC](https://forum.cadet-web.de/t/issues-possibly-related-to-pypi-metapackage-installation-without-conda/1408/1 "2026-03-09T08:45:35Z")
### Expected behavior. Repicating the codes from [CADET-Workshop/02 CADET Fundamentals/02.1 first steps/02.1.1\_breakthrough.ipynb at solution · cadet/CADET-Workshop · GitHub](https://github.com/cadet/CADET-Workshop/blob/solution/02%20CADET%20Fundamentals/02.1%20first%20steps/02.1.1_breakthrough.ipynb) 1. Successful autodetection of CADET with “simulator = Cadet()”. 2. No errors with “simulation\_results = simulator.simulate(process)”. ### Actual behavior 1. Cannot autodetect CADET until the path is manually specified, even then, only the built-from-source CADET-Core was detected (neither via conda nor pip) 2. CADETProcess.CADETProcessError.CADETProcessError: CADET Error: Simulation failed with IO ERROR: Field “NPARTYPE” does not exist in group /input/model/unit\_002 when trying to run the simulation. ### How to produce bug (including a minimal reproducible example) 1. Create a basic, default virtual environment on Visual Studio 2026 2. Activate the virtual environment 3. Run “pip install cadet” in PowerShell 4. Copy the codes from [CADET-Workshop/02 CADET Fundamentals/02.1 first steps/02.1.1\_breakthrough.ipynb at solution · cadet/CADET-Workshop · GitHub](https://github.com/cadet/CADET-Workshop/blob/solution/02%20CADET%20Fundamentals/02.1%20first%20steps/02.1.1_breakthrough.ipynb) ---
**Author:** ![h.lanzrath](https://forum.cadet-web.de/user_avatar/forum.cadet-web.de/h.lanzrath/32/1186_2.png) [@h.lanzrath](https://forum.cadet-web.de/u/h.lanzrath)\ **Post date:** [March 9, 2026, 9:14am UTC](https://forum.cadet-web.de/t/issues-possibly-related-to-pypi-metapackage-installation-without-conda/1408/3 "2026-03-09T09:14:30Z")
Hi ucbevng, Welcome to the forum and thanks for posting your issue! To better understand what might be causing the problem, I would need a bit more information. When you are inside your virtual environment, could you please run the following commands and post the output? ```auto where cadet where cadet-core where cadet-cli pip list ``` In particular, it would be helpful to see which CADET-related packages and versions are installed. My suspicion is that you have a CADET build from source on your **global PATH** , possibly a pre-release version that is not compatible with CADET-Process. If that path is visible inside your virtual environment, CADET-Process might detect that installation instead of the CADET version associated with your environment (for example the one installed via pip or conda). In that case, CADET-Process may end up using the wrong executable. One way to resolve this is to ensure that the PATH inside the virtual environment points to the correct CADET installation. Alternatively, you can explicitly specify the CADET installation when creating the simulator: ```python simulator = Cadet(install_path="path/to/cadet") ``` Here, `install_path` should point to the **directory of the desired CADET installation** (the directory of the `cadet-core` pip package that contains the `cadet-cli`). If you report back with the requested information, I am confident we can narrow down the issue and find a solution. Best, Hannah ---
**Author:** ![ucbevng](https://forum.cadet-web.de/letter_avatar_proxy/v4/letter/u/6f9a4e/32.png) [@ucbevng](https://forum.cadet-web.de/u/ucbevng)\ **Post date:** [March 11, 2026, 8:43am UTC](https://forum.cadet-web.de/t/issues-possibly-related-to-pypi-metapackage-installation-without-conda/1408/4 "2026-03-11T08:43:00Z")
![Screenshot 2026-03-09 215731](https://forum.cadet-web.de/uploads/default/original/2X/4/435dcfc69175ddbc8dc476e2ede8f04cc822b42d.jpeg) The screenshot above is the “where” commands and pip list output. I just merged 2 screenshots together because I do not know how to transfer the output from VS2026 to a .txt file 😅 . `simulator = Cadet(install_path=“C:\Users\VN62442\source\repos\SMB\SMB\vcadet\Lib\site-packages\cadet_core\bin”)`resulted in `SyntaxError: (unicode error) ‘unicodeescape’ codec can’t decode bytes in position 2-3: truncated \UXXXXXXXX escape` `simulator = Cadet(install_path=r"C:\Users\VN62442\source\repos\SMB\SMB\vcadet\Lib\site-packages\cadet_core\bin")`resulted in autodetection failure (this file path is towards `cadet-cli.exe`in the virtual environment). So far, only `simulator = Cadet(install_path=r"C:\Users\VN62442\source\repos\cadet-core\out\install\aRELEASE")`succeeded in detection (this is the file path of the locally-built CADET-Core. I hope these are what you need. Coding in general is not my forte 😅 ---
**Author:** ![h.lanzrath](https://forum.cadet-web.de/user_avatar/forum.cadet-web.de/h.lanzrath/32/1186_2.png) [@h.lanzrath](https://forum.cadet-web.de/u/h.lanzrath)\ **Post date:** [March 11, 2026, 8:58am UTC](https://forum.cadet-web.de/t/issues-possibly-related-to-pypi-metapackage-installation-without-conda/1408/5 "2026-03-11T08:58:19Z")
Hi ucbevng, The pip list looks alright, the “where” command unfortunately didn’t print any outputs, since you are in the power shell. Can you possible use the Command Line Interface (CMD) instead and repeat the commands? I will have a look at how the autodetect interacts with the CADET-Core package in the meantime. Thanks, Hannah ---
**Author:** ![h.lanzrath](https://forum.cadet-web.de/user_avatar/forum.cadet-web.de/h.lanzrath/32/1186_2.png) [@h.lanzrath](https://forum.cadet-web.de/u/h.lanzrath)\ **Post date:** [March 11, 2026, 9:11am UTC](https://forum.cadet-web.de/t/issues-possibly-related-to-pypi-metapackage-installation-without-conda/1408/6 "2026-03-11T09:11:55Z")
> [@ucbevng](#): > > Cadet(install\_path=r"C:\Users\VN62442\source\repos\SMB\SMB\vcadet\Lib\site-packages\cadet\_core\bin") Can you try `Cadet(install_path=r"C:\Users\VN62442\source\repos\SMB\SMB\vcadet\Lib\site-packages\cadet_core")` or `Cadet(install_path=r"C:\Users\VN62442\source\repos\SMB\SMB\vcadet\Lib\site-packages\cadet_core\bin\cadet-cli")` Do these work for you? ---
**Author:** ![ucbevng](https://forum.cadet-web.de/letter_avatar_proxy/v4/letter/u/6f9a4e/32.png) [@ucbevng](https://forum.cadet-web.de/u/ucbevng)\ **Post date:** [March 12, 2026, 8:20am UTC](https://forum.cadet-web.de/t/issues-possibly-related-to-pypi-metapackage-installation-without-conda/1408/7 "2026-03-12T08:20:39Z")
![image](https://forum.cadet-web.de/uploads/default/original/2X/c/cbf8d30ccb1e6cec42719753fea6f1f3e87d9b3e.png) This cmd output is after I activated vcadet in PowerShell. > [@h.lanzrath](#): > > Cadet(install\_path=r"C:\Users\VN62442\source\repos\SMB\SMB\vcadet\Lib\site-packages\cadet\_core") This yielded `Test simulation completed successfully`, no “NPARTYPE” error. > [@h.lanzrath](#): > > Cadet(install\_path=r"C:\Users\VN62442\source\repos\SMB\SMB\vcadet\Lib\site-packages\cadet\_core\bin\cadet-cli") This resulted in autodetection failure. ---
**Author:** ![h.lanzrath](https://forum.cadet-web.de/user_avatar/forum.cadet-web.de/h.lanzrath/32/1186_2.png) [@h.lanzrath](https://forum.cadet-web.de/u/h.lanzrath)\ **Post date:** [March 13, 2026, 9:24am UTC](https://forum.cadet-web.de/t/issues-possibly-related-to-pypi-metapackage-installation-without-conda/1408/8 "2026-03-13T09:24:54Z")
Hi ucbevng, That exactly confirms my suspicion. At some point, the path to `cadet-cli` was added to your **global PATH environment variable**. Because of that, it appears when you run `where cadet-cli`. CADET-Process detects the executable built from source on the PATH and assumes that this is the default CADET installation you want to use. This behaviour is intended and not a CADET issue. The PATH variable is controlled by the user, and any executable placed there will be detected automatically. Also note that **if you are not working inside an isolated environment (e.g., a conda environment or a Python venv)**, this can easily lead to the issue you are seeing. On Windows you effectively only have **one global PATH** , which means you can only have **one CADET installation reliably available via `cadet-cli`** at a time. If multiple CADET installations exist on your system, the one that appears first on the PATH will be used, which may not be the one you intended. You now have three options. ### Option 1: Remove CADET from the global PATH and update with desired version (not recommended) You could remove the CADET entry from the global PATH and replace it with the installation you actually want to use. On Windows this can be done via: Start Menu → search for **Environment Variables** → **Edit the system environment variables** → **Environment Variables** → select **Path** → **Edit**. There you can remove the CADET entry or add a different one pointing to another CADET installation. After changing the PATH, you need to open a **new terminal** for the changes to take effect. However, this approach is usually not ideal if you work with multiple CADET builds. ### Option 2: Add the correct CADET installation to the environment you are using Instead of relying on the global PATH, you can add the CADET installation to the PATH **inside the environment you are working in**. #### For a Conda environment Activate your environment: ```bash conda activate your_env ``` Temporarily extend the PATH: ```bash set PATH=C:\path\to\cadet;%PATH% ``` If you want this to persist for that environment: ```bash conda env config vars set PATH=C:\path\to\cadet;%PATH% ``` Then deactivate and activate the environment again. #### For a Python venv Activate the environment and edit the activation script: ```auto \Scripts\activate.bat ``` Add a line such as: ```auto set PATH=C:\path\to\cadet;%PATH% ``` This ensures that the correct CADET version is used whenever that environment is activated. ### Option 3: Direct configuration (recommended in your case) In your situation, explicitly setting the CADET installation path is likely the simplest solution: ```python Cadet( install_path=r"C:\Users\VN62442\source\repos\SMB\SMB\vcadet\Lib\site-packages\cadet_core" ) ``` This bypasses automatic detection and directly tells CADET-Process which installation should be used. You already confirmed that this works for you, right? Does this solve your problem? Cheers, Hannah ---
**Author:** ![ucbevng](https://forum.cadet-web.de/letter_avatar_proxy/v4/letter/u/6f9a4e/32.png) [@ucbevng](https://forum.cadet-web.de/u/ucbevng)\ **Post date:** [March 14, 2026, 1:13am UTC](https://forum.cadet-web.de/t/issues-possibly-related-to-pypi-metapackage-installation-without-conda/1408/9 "2026-03-14T01:13:39Z")
> Cadet( > install\_path=r"C:\Users\VN62442\source\repos\SMB\SMB\vcadet\Lib\site-packages\cadet\_core" > ) I’ve attempted the other 2 methods, but it seems like I’m not savvy enough to get them to work. Direct configuration seems to be the solution, but I find it strange that some PATH (I don’t recall which one) can lead to `NPARTYPE`missing error. Anyways, I guess I will have to stick with direct configuration for now, thank you! ---
**Author:** ![j.breuer](https://forum.cadet-web.de/user_avatar/forum.cadet-web.de/j.breuer/32/1139_2.png) [@j.breuer](https://forum.cadet-web.de/u/j.breuer)\ **Post date:** [March 14, 2026, 10:29am UTC](https://forum.cadet-web.de/t/issues-possibly-related-to-pypi-metapackage-installation-without-conda/1408/10 "2026-03-14T10:29:58Z")
> but I find it strange that some PATH (I don’t recall which one) can lead to `NPARTYPE` missing error The PATH is pointing to a newer CADET-Core version, probably a v6 pre-release or a master build. For v6 (which is not released yet, only pre-releases as described [here](https://forum.cadet-web.de/t/cadet-core-v6-pre-releases-and-release-strategy/1359)) there will be some interface changes. Depending on the unit operation, `NPARTYPE` will be a mandatory field. Per default, conda and PyPi install the latest stable release which is v5.1.X Pre-releases can be installed via conda/PyPi as described here: [CADET-Core v6 pre-releases and release strategy](https://forum.cadet-web.de/t/cadet-core-v6-pre-releases-and-release-strategy/1359) Best regards, Jan ---
**Author:** ![h.lanzrath](https://forum.cadet-web.de/user_avatar/forum.cadet-web.de/h.lanzrath/32/1186_2.png) [@h.lanzrath](https://forum.cadet-web.de/u/h.lanzrath)\ **Post date:** [March 16, 2026, 8:55am UTC](https://forum.cadet-web.de/t/issues-possibly-related-to-pypi-metapackage-installation-without-conda/1408/11 "2026-03-16T08:55:05Z")
> [@h.lanzrath](#): > > My suspicion is that you have a CADET build from source on your **global PATH** , possibly a pre-release version that is not compatible with CADET-Process. As written in my first post, I agree with what @j.breuer suspects. If you type ```auto cadet-cli --version ``` you will likely see, that you have a pre-release version buillt from source which is on your global PATH. Best, Hannah ---
**Author:** ![system](https://forum.cadet-web.de/uploads/default/original/2X/4/4ec43a357aeb35dcb4e6620649f54e8e6591b258.png) [@system](https://forum.cadet-web.de/u/system)\ **Post date:** [March 18, 2026, 8:55am UTC](https://forum.cadet-web.de/t/issues-possibly-related-to-pypi-metapackage-installation-without-conda/1408/12 "2026-03-18T08:55:52Z")
This topic was automatically closed 2 days after the last reply. New replies are no longer allowed. ---
**Author:** ![h.lanzrath](https://forum.cadet-web.de/user_avatar/forum.cadet-web.de/h.lanzrath/32/1186_2.png) [@h.lanzrath](https://forum.cadet-web.de/u/h.lanzrath)\ **Post date:** [April 10, 2026, 2:34pm UTC](https://forum.cadet-web.de/t/issues-possibly-related-to-pypi-metapackage-installation-without-conda/1408/13 "2026-04-10T14:34:41Z")
Also see [CADET-Core PyPi distribution does not work with CADET-Process Autodetect · Issue #666 · cadet/CADET-Core · GitHub](https://github.com/cadet/CADET-Core/issues/666).