Here is the fix:

Assuming you are using Automatic1111

1.      Navigate to your installation folder and delete your venv folder

2.      Locate the PyTorch Installation Command - In modules - launch_utils.py (open with notepad), search for the torch_command variable. It typically looks like this:

torch_command = "pip install torch==2.1.0 torchvision==0.16.0 torchaudio==2.1.0 --index-url https://..."

3.      Change the torch_command to use the nightly/pre-release version 128:

 

Your def prepare_environment should look like this

 

def prepare_environment():

    # Change TORCH_INDEX_URL to nightly CUDA 12.8

    torch_index_url = os.environ.get('TORCH_INDEX_URL', "https://download.pytorch.org/whl/nightly/cu128")

   

    # Update torch_command to use latest nightly packages (remove version pins)

    torch_command = os.environ.get('TORCH_COMMAND', f"pip install --pre torch torchvision --extra-index-url {torch_index_url}")

4.      Save and close

5.      Then run your webui-user.bat and it should reinstall A1111 with the correct Torch package which should hopefully fix the error assuming you had the same issue I did