ComfyUI No Module Named 'sageattention' Explained (Simply)

You’re staring at the console, and there it is again. That annoying red text screaming ModuleNotFoundError: No module named 'sageattention'. Honestly, it’s enough to make you want to go back to pencil and paper.

You probably just tried to run a high-end Wan2.1 or a heavy video workflow, and ComfyUI decided it wasn’t going to cooperate. SageAttention is basically the "secret sauce" for 2026-era generative AI, offering up to 2-5x speedups over traditional FlashAttention. But getting it to actually run in ComfyUI? That’s where the blood, sweat, and tears come in.

Most of the time, this happens because SageAttention isn't just a simple "click install" node. It’s a complex piece of software that needs a very specific handshake between your GPU drivers, Python version, and a secondary tool called Triton. If one of those is off by a single version number, the whole thing falls apart.

Why does ComfyUI keep losing SageAttention?

The most common culprit is the Portable Version of ComfyUI. Because the portable zip comes with its own "embedded" Python, it doesn't see the packages you install on your system globally. You might have run pip install sageattention in a random terminal, but ComfyUI is living in its own little bubble, completely unaware of what you just did.

Then there’s the Triton problem. On Windows, Triton is notoriously finicky. SageAttention depends on Triton to handle the heavy math on your NVIDIA card. If you don’t have triton-windows installed inside the specific environment ComfyUI uses, the SageAttention module will fail to load every single time.

The Fix: Getting it installed the right way

Don't just start typing commands blindly. First, you need to know where your ComfyUI is actually living.

If you are using the Windows Portable version, you have to use the python_embedded folder. Open a command prompt inside your main ComfyUI folder and run this:

.\python_embeded\python.exe -m pip install triton-windows

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Once Triton is in place, you can try the standard SageAttention install:

.\python_embeded\python.exe -m pip install sageattention

However, if you're on a newer setup—like an RTX 5090 or running the latest 2026 updates—you might need a specific "wheel" file. Many users have found that the standard pip install fails because of C++ compilation errors. In that case, you’ll want to head over to the SageAttention GitHub releases and find the .whl file that matches your Torch version (usually 2.7 or 2.8+ these days).

Dealing with the "Missing Python.h" Error

If you see a wall of text talking about a missing Python.h file, don't panic. This just means your environment is missing the "headers" needed to compile the code. This is super common in the portable version because it’s stripped down to save space.

You have two real choices here:

1. The Hack: Find a full installation of Python 3.12 (or whatever version you're using), copy the include and libs folders, and paste them directly into your ComfyUI_windows_portable\python_embeded directory. It's ugly, but it works.
2. The Smart Way: Use a one-click installer. Projects like comfyui-triton-and-sageattention-installer on GitHub have become lifesavers. They automate the detection of your CUDA version and force the installation through.

It's installed, but ComfyUI still won't use it?

So you've verified the module exists, but the "Patch Sage Attention" node is still red. This is usually a startup argument issue. You need to tell ComfyUI to actually enable the optimization.

If you use the run_nvidia_gpu.bat file, right-click it and select "Edit." Add --use-sage-attention to the end of the command line. For ComfyUI Desktop users, you’ll need to peek into your comfy.settings.json file and add "use-sage-attention": "" under the LaunchArgs section.

Actionable Next Steps

To get back to generating, follow this specific sequence:

• Check your Torch version: Run pip show torch in your ComfyUI terminal. You need to know if you're on cu124, cu128, or the newer cu130.
• Install Triton first: You cannot skip this. Use pip install triton-windows (or the specific version matching your Torch).
• Use a Pre-compiled Wheel: If the standard install fails, download the matching .whl for SageAttention from GitHub and install it directly via pip install [filename].whl.
• Verify with the Console: When ComfyUI starts, look for a line that says SageAttention: Enabled or SaeAttention (triton). If you see "No module named," repeat the steps specifically inside the .venv or python_embedded folder.
• Downgrade if necessary: If you're on PyTorch 2.9+ and everything is breaking, many users are finding stability by rolling back to Torch 2.7.1+cu128, which currently has the best compatibility with SageAttention 2.2.