05 · Install errorsRead the first real error, not the last symptom
Keep the console open, copy the first traceback, and record the route, GPU, driver, Python version, and package filename before changing anything.
PYTHONUnsupported or mixed Python
Use a separate compatible 64-bit environment. A system Python upgrade can break an existing virtual environment even when Forge files did not change.
GPU / TORCHCUDA is unavailable or the architecture is unsupported
Verify the NVIDIA driver and the PyTorch build together. An RTX 50-series architecture error is not fixed by suppressing the CUDA test.
Check current PyTorch options ↗NETWORKA dependency or repository download fails
Preserve the exact URL and error. Retry only after checking connectivity, proxy, certificate, antivirus, and free disk space; repeated partial installs can obscure the cause.
See a community dependency report ↗BINARY PACKAGESNumPy or another compiled package is incompatible
Do not scatter global pip install commands across environments. Recreate or repair the Forge environment with compatible pinned packages.
See a reported NumPy mismatch ↗LOCALHOSTThe browser cannot connect
Return to the console. If the process exited, localhost has nothing to connect to. If it is running, use the exact local address it printed and check whether security software blocked the process.
MODELThe UI opens but no checkpoint appears
The application is installed; the model is missing or in the wrong folder. Continue with the first-run guide instead of reinstalling Forge.
Set up the first model →