Windows Installation

See how to install Unsloth on Windows with or without WSL.

Method #1 - Windows directly:

Python 3.13 does not support Unsloth. Use 3.12, 3.11 or 3.10.

Need help or experiencing an error? Ask on our GitHub Discussions thread for Windows support!

1

Install NVIDIA Video Driver

You should install the latest version of your GPUs driver. Download drivers here: NVIDIA GPU Drive

2

Install Visual Studio C++

You will need Visual Studio, with C++ installed. By default, C++ is not installed with Visual Studio, so make sure you select all of the C++ options. Also select options for Windows 10/11 SDK.

• Launch the Installer here: Visual Studio Community Edition

• In the installer, navigate to individual components and select all the options listed here:

  • .NET Framework 4.8 SDK

  • .NET Framework 4.7.2 targeting pack

  • C# and Visual Basic Roslyn compilers

  • MSBuild

  • MSVC v143 - VS 2022 C++ x64/x86 build tools

  • C++ 2022 Redistributable Update

  • C++ CMake tools for Windows

  • C++/CLI support for v143 build tools (Latest)

  • MSBuild support for LLVM (clang-cl) toolset

  • C++ Clang Compiler for Windows (19.1.1)

  • Windows 11 SDK (10.0.22621.0)

  • Windows Universal CRT SDK

  • C++ 2022 Redistributable MSMs

Easier method: Or you can open an elevated Command Prompt or PowerShell:

• Search for "cmd" or "PowerShell", right-click it, and choose "Run as administrator."

• Paste and run this command (update the Visual Studio path if necessary):

"C:\Program Files (x86)\Microsoft Visual Studio\Installer\vs_installer.exe" modify ^
--installPath "C:\Program Files\Microsoft Visual Studio\2022\Community" ^
--add Microsoft.Net.Component.4.8.SDK ^
--add Microsoft.Net.Component.4.7.2.TargetingPack ^
--add Microsoft.VisualStudio.Component.Roslyn.Compiler ^
--add Microsoft.Component.MSBuild ^
--add Microsoft.VisualStudio.Component.VC.Tools.x86.x64 ^
--add Microsoft.VisualStudio.Component.VC.Redist.14.Latest ^
--add Microsoft.VisualStudio.Component.VC.CMake.Project ^
--add Microsoft.VisualStudio.Component.VC.CLI.Support ^
--add Microsoft.VisualStudio.Component.VC.Llvm.Clang ^
--add Microsoft.VisualStudio.ComponentGroup.ClangCL ^
--add Microsoft.VisualStudio.Component.Windows11SDK.22621 ^
--add Microsoft.VisualStudio.Component.Windows10SDK.19041 ^
--add Microsoft.VisualStudio.Component.UniversalCRT.SDK ^
--add Microsoft.VisualStudio.Component.VC.Redist.MSM

3

Install Python and CUDA Toolkit

Follow the instructions to install CUDA Toolkit.

Then install Miniconda (which has Python) here: https://www.anaconda.com/docs/getting-started/miniconda/install

4

Install PyTorch

You will need the correct version of PyTorch that is compatible with your CUDA drivers, so make sure to select them carefully. Install PyTorch

5

Install Unsloth

Open Conda command prompt or your terminal with Python and run the command:

pip install "unsloth[windows] @ git+https://github.com/unslothai/unsloth.git"

If you're using GRPO or plan to use vLLM, currently vLLM does not support Windows directly but only via WSL or Linux.

Notes

To run Unsloth directly on Windows:

• Install Triton from this Windows fork and follow the instructions here (be aware that the Windows fork requires PyTorch >= 2.4 and CUDA 12)

• In the SFTTrainer, set dataset_num_proc=1 to avoid a crashing issue:

trainer = SFTTrainer(
    dataset_num_proc=1,
    ...
)

Advanced/Troubleshooting

For advanced installation instructions or if you see weird errors during installations:

1. Install torch and triton. Go to https://pytorch.org to install it. For example pip install torch torchvision torchaudio triton

2. Confirm if CUDA is installated correctly. Try nvcc. If that fails, you need to install cudatoolkit or CUDA drivers.

3. Install xformers manually. You can try installing vllm and seeing if vllm succeeds. Check if xformers succeeded with python -m xformers.info Go to https://github.com/facebookresearch/xformers. Another option is to install flash-attn for Ampere GPUs.

4. Double check that your versions of Python, CUDA, CUDNN, torch, triton, and xformers are compatible with one another. The PyTorch Compatibility Matrix may be useful.

5. Finally, install bitsandbytes and check it with python -m bitsandbytes

---

Method #2 - Windows using PowerShell:

Step 1: Install Prerequisites

1. Install NVIDIA CUDA Toolkit:

   • Download and install the appropriate version of the NVIDIA CUDA Toolkit from CUDA Downloads.

   • Reboot your system after installation if prompted.

   • Note: No additional setup is required after installation for Unsloth.

2. Install Microsoft C++ Build Tools:

   • Download and install Microsoft Build Tools for Visual Studio from the official website.

   • During installation, select the C++ build tools workload. Ensure the MSVC compiler toolset is included.

3. Set Environment Variables for the C++ Compiler:

   • Open the System Properties window (search for "Environment Variables" in the Start menu).

   • Click "Environment Variables…".

   • Add or update the following under System variables:

     • CC: Path to the cl.exe C++ compiler. Example (adjust if your version differs):

       C:\Program Files\Microsoft Visual Studio\2022\BuildTools\VC\Tools\MSVC\14.34.31933\bin\Hostx64\x64\cl.exe

     • CXX: Same path as CC.

   • Click OK to save changes.

   • Verify: Open a new terminal and type cl. It should show version info.

4. Install Conda

   1. Download and install Miniconda from the official website

   2. Follow installation instruction from the website

   3. To check whether conda is already installed, you can test it with conda in your PowerShell

Step 2: Run the Unsloth Installation Script

1. Download the unsloth_windows.ps1 PowerShell script by going through this link.

2. Open PowerShell as Administrator:

   • Right-click Start and select "Windows PowerShell (Admin)".

3. Navigate to the script’s location using cd:

   cd path\to\script\folder

4. Run the script:

   powershell.exe -ExecutionPolicy Bypass -File .\unsloth_windows.ps1

Step 3: Using Unsloth

Activate the environment after the installation completes:

conda activate unsloth_env

Unsloth and its dependencies are now ready!

---

Method #3 - Windows via WSL:

WSL is Window's subsystem for Linux.

1. Install python though Python's official site.

2. Start WSL (Should already be preinstalled). Open command prompt as admin then run:

wsl -d ubuntu

Optional: If WSL is not preinstalled, go to the Microsoft store and search "Ubuntu" and the app that says Ubuntu will be WSL. Install it and run it and continue from there.

1. Update WSL:

sudo apt update && sudo apt upgrade -y

1. Install pip:

sudo apt install python3-pip

1. Install unsloth:

pip install unsloth

1. Optional: Install Jupyter Notebook to run in a Colab like environment:

pip3 install notebook

1. Launch Jupyter Notebook:

jupyter notebook

1. Download any Colab notebook from Unsloth, import it into your Jupyter Notebook, adjust the parameters as needed, and execute the script.