Ollama: bind: address already in use (port 11434)

Ollama tries to bind port 11434 on startup, but another process (almost always a previous Ollama instance that didn't shut down cleanly) already has it. On Windows the Ollama service often runs in the background even when the GUI is closed.

On macOS / Linux:

# Find and kill the existing Ollama process
lsof -i :11434
kill -9 <PID>
ollama serve

On Windows:

# Find which process owns port 11434
netstat -ano | findstr :11434
# Kill it (last column is the PID)
taskkill /F /PID <PID>

Or, if you have admin rights, restart the Ollama service:

Stop-Service -Name "Ollama"
Start-Service -Name "Ollama"

Run on a different port if you need both instances (rare):

OLLAMA_HOST=0.0.0.0:11500 ollama serve