[Question] isaaclab.bat --install cannot find python executable at path when following official installation procedure

[tueboesen]

I am following the recommended way of installing isaacsim and isaac lab for windows as given here:
https://isaac-sim.github.io/IsaacLab/main/source/setup/installation/pip_installation.html

Installing isaacsim from pip works fine, but the trouble starts after I clone isaac lab into my project folder.

At that point my root project folder looks like this:

Mode                 LastWriteTime         Length Name
----                 -------------         ------ ----
d-----         6/10/2025   9:46 AM                .idea
d-----          6/6/2025   8:53 AM                .venv
d-----          6/3/2025  11:39 AM                docs
d-----         6/10/2025   9:46 AM                IsaacLab
d-----         6/10/2025   8:58 AM                src
-a----          6/3/2025  11:38 AM           4319 .gitignore
-a----         6/10/2025   9:33 AM            735 pyproject.toml
-a----          6/3/2025  11:40 AM           7259 README.md
-a----         6/10/2025   9:15 AM         176795 uv.lock

If I then cd into IsaacLab and run:

./isaaclab.bat --install

I get the following error:
(algorithmic-test-bench) PS C:\Users\714212\PycharmProjects\algorithmic-test-bench\IsaacLab> ./isaaclab.bat --install
[INFO] Installing extensions inside the Isaac Lab repository...
"C:\Users\714212\PycharmProjects\algorithmic-test-bench\IsaacLab\\source\isaaclab"
[ERROR] Unable to find any Python executable at path: 
This could be due to the following reasons:
1. Conda environment is not activated.
2. Python executable is not available at the default path: C:\Users\714212\PycharmProjects\algorithmic-test-bench\IsaacLab\\_isaac_sim\python.bat
    module: "C:\Users\714212\PycharmProjects\algorithmic-test-bench\IsaacLab\\source\isaaclab"
'-m' is not recognized as an internal or external command,
operable program or batch file.
"C:\Users\714212\PycharmProjects\algorithmic-test-bench\IsaacLab\\source\isaaclab_assets"
[ERROR] Unable to find any Python executable at path: 
This could be due to the following reasons:
1. Conda environment is not activated.
2. Python executable is not available at the default path: C:\Users\714212\PycharmProjects\algorithmic-test-bench\IsaacLab\\_isaac_sim\python.bat
    module: "C:\Users\714212\PycharmProjects\algorithmic-test-bench\IsaacLab\\source\isaaclab_assets"
'-m' is not recognized as an internal or external command,
operable program or batch file.
"C:\Users\714212\PycharmProjects\algorithmic-test-bench\IsaacLab\\source\isaaclab_mimic"
[ERROR] Unable to find any Python executable at path: 
This could be due to the following reasons:
1. Conda environment is not activated.
2. Python executable is not available at the default path: C:\Users\714212\PycharmProjects\algorithmic-test-bench\IsaacLab\\_isaac_sim\python.bat
    module: "C:\Users\714212\PycharmProjects\algorithmic-test-bench\IsaacLab\\source\isaaclab_mimic"
'-m' is not recognized as an internal or external command,
operable program or batch file.
"C:\Users\714212\PycharmProjects\algorithmic-test-bench\IsaacLab\\source\isaaclab_rl"
[ERROR] Unable to find any Python executable at path: 
This could be due to the following reasons:
1. Conda environment is not activated.
2. Python executable is not available at the default path: C:\Users\714212\PycharmProjects\algorithmic-test-bench\IsaacLab\\_isaac_sim\python.bat
    module: "C:\Users\714212\PycharmProjects\algorithmic-test-bench\IsaacLab\\source\isaaclab_rl"
'-m' is not recognized as an internal or external command,
operable program or batch file.
"C:\Users\714212\PycharmProjects\algorithmic-test-bench\IsaacLab\\source\isaaclab_tasks"
[ERROR] Unable to find any Python executable at path: 
This could be due to the following reasons:
1. Conda environment is not activated.
2. Python executable is not available at the default path: C:\Users\714212\PycharmProjects\algorithmic-test-bench\IsaacLab\\_isaac_sim\python.bat
    module: "C:\Users\714212\PycharmProjects\algorithmic-test-bench\IsaacLab\\source\isaaclab_tasks"
'-m' is not recognized as an internal or external command,
operable program or batch file.
[INFO] Installing extra requirements such as learning frameworks...
[INFO] Installing all rl-frameworks.
'-m' is not recognized as an internal or external command,
operable program or batch file.
[INFO] Setting up vscode settings...
[ERROR] Unable to find any Python executable at path: 
This could be due to the following reasons:
1. Conda environment is not activated.
2. Python executable is not available at the default path: C:\Users\714212\PycharmProjects\algorithmic-test-bench\IsaacLab\\_isaac_sim\python.bat

The error messages are pretty clear in that isaaclab.bat is missing a python environment, but I'm not sure why that is or what exactly I should do to fix this?

Additional Information

My pyproject.toml looks like this:

[project]
name = "algorithmic-test-bench"
version = "0.1.0"
description = "Add your description here"
readme = "README.md"
requires-python = ">=3.10,<3.11"
dependencies = [
  "torch==2.5.1",
  "torchvision==0.20.1",
  "isaacsim[all,extscache]==4.5.0",
]

[build-system]
requires = ["setuptools", "wheel", "toml"]
build-backend = "setuptools.build_meta"

[tool.uv.sources]
isaacsim = { index = "nvidia" }
torch = { index = "pytorch-cu121"}
torchvision = { index = "pytorch-cu121"}

[[tool.uv.index]]
name = "nvidia"
url = "https://pypi.nvidia.com"
explicit = true

[[tool.uv.index]]
name = "pytorch-cu121"
url = "https://download.pytorch.org/whl/cu121"
explicit = true

[RandomOakForest]

Thank you for posting this. Before running the installation of Isaac Lab, are you activating your conda environment?

conda create -n env_isaaclab python=3.10
conda activate env_isaaclab

[tueboesen]

I am not using a conda environment, but rather a virtual environment created through uv, as indicated in the pyproject.toml I showed above.
The virtual environment is activated when I run the above command.

[RandomOakForest]

Interesting. Where is your python.bat?

[tueboesen]

I just did a search in the project folder and found one python.bat file, which was located in:
algorithmic-test-bench\.venv\Lib\site-packages\omni\dev\tools\packman

where algorithmic-test-bench is the root project folder.

I might be using this file implicitly whenever I call python, but if so I was not aware of it and have certainly not set it manually at any point.

[RandomOakForest]

Following up, I will move this post to our Discussions section. In the meantime, note that this typically results from a misconfigured or inactive Python environment. Here’s how you may be able to resolve it.

Why This Error Occurs

The error message:

Unable to find any Python executable at path:
This could be due to the following reasons:

1. Conda environment is not activated.
2. Python executable is not available at the default path: ..._isaac_sim\python.bat

indicates that the script is searching for a Python interpreter in a specific location (usually a bundled Isaac Sim Python), but it cannot find it. This is often because:

• The required Conda or virtual environment is not activated.
• The environment was not set up according to the recommended steps.
• The script expects a certain directory structure or environment variable that is missing.

Official Installation Steps (Windows, Pip Method)

1. Create and Activate a Python 3.10 Environment

• Using Conda (recommended):

conda create -n env_isaaclab python=3.10
conda activate env_isaaclab

• Or using venv:

python3.10 -m venv env_isaaclab
env_isaaclab\Scripts\activate

2. Install PyTorch (CUDA version must match your GPU drivers):

pip install torch==2.5.1 torchvision==0.20.1 --index-url https://download.pytorch.org/whl/cu121

3. Upgrade pip:

python -m pip install --upgrade pip

4. Install Isaac Sim via pip:

pip install 'isaacsim[all,extscache]==4.5.0' --extra-index-url https://pypi.nvidia.com

5. Clone Isaac Lab and Install:

git clone https://github.com/isaac-sim/IsaacLab.git
cd IsaacLab
isaaclab.bat --install

Key Points to Check

• Always activate your environment before running isaaclab.bat --install. If you open a new terminal, you must reactivate it.
• Do not expect a _isaac_sim/python.bat when using the pip installation. The script should use the Python from your active environment.
• If you see errors about '-m' is not recognized..., it usually means the environment is not active or the python command is not available in your PATH.

What To Do If You Still Get the Error

• Double-check that your environment is active: The prompt should show (env_isaaclab) or your chosen environment name.
• Run where python in your terminal. The first result should point to your environment’s Python executable.
• Try running the install command as:

isaaclab.bat --install

(not ./isaaclab.bat --install in PowerShell; use isaaclab.bat --install in Command Prompt or PowerShell).

• If you use PyCharm or another IDE, ensure the terminal inside the IDE is using the correct environment.

Verifying Installation

After installation, test with:

isaaclab.bat -p scripts\tutorials\00_sim\create_empty.py

or

python scripts\tutorials\00_sim\create_empty.py

This should launch Isaac Sim with a black viewport if everything is set up correctly¹.

Additional Tips

• Do not mix installation methods (pip vs. binary). Stick to one.
• If you previously installed Isaac Sim using the binary installer, remove or rename any _isaac_sim folders in your project to avoid confusion.
• If you encounter persistent issues, try creating a fresh environment and repeating the steps above.

Summary Table

Step	Command/Action
Create environment	conda create -n env_isaaclab python=3.10
Activate environment	conda activate env_isaaclab
Install PyTorch	pip install torch==2.5.1 torchvision==0.20.1 --index-url ...
Upgrade pip	python -m pip install --upgrade pip
Install Isaac Sim	pip install 'isaacsim[all,extscache]==4.5.0' --extra-index-url ...
Clone Isaac Lab	git clone https://github.com/isaac-sim/IsaacLab.git
Install Isaac Lab	cd IsaacLab then isaaclab.bat --install
Test installation	isaaclab.bat -p scripts\tutorials\00_sim\create_empty.py

If you follow these steps and ensure your environment is properly activated, the error should be resolved. If not, please provide the output of where python and confirm your environment activation for further troubleshooting¹.

Footnotes

1. https://isaac-sim.github.io/IsaacLab/main/source/setup/installation/pip_installation.html ↩ ↩²

[TechArtistG]

I'm getting the same errors trying to install IsaacLab using UV

[azazdeaz]

I'm getting the same errors trying to install IsaacLab using UV

I found that uv venv doesn't install pip in the virtual env by default, but isaaclab.sh uses pip list to check if isaacsim is available.

So uv pip install pip can solve the issue.