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Troubleshooting

If you are having issues with Lc0, here are some common problems and their solutions.

Memory issues

Running out of memory

Unlike traditional A/B chess engines, Lc0 has to keep entire search tree in memory. That means that as the search goes, memory consumption increases. Lc0 requires roughly 250-350 bytes of memory per node, that means that typical RAM sizes can only handle so many nodes:

Running without GUI

This guide will help you test if Leela Chess Zero is working correctly by running it without any chess GUI program.

Step-by-Step Instructions

Step 1: Find the lc0 file

  1. Open File Explorer (the folder icon in your taskbar, or press Windows key + E)
  2. Navigate to the folder where you installed Leela Chess Zero
    • This is usually in a folder like C:\Lc0\ or wherever you extracted the files
  3. Look for a file named lc0 (it will show as type “Application” or “Windows Application”)
    • Note: You might not see the .exe extension - that’s normal in Windows

Step 2: Run lc0 directly

  1. Double-click on the lc0 file
  2. A black window (Command Prompt) should open
    • Don’t worry if it looks intimidating - this is normal!
    • You should see some text appear, possibly including version information

Step 3: Test the engine

  1. In the black window, type exactly: go nodes 1000
  2. Press Enter
  3. Wait for the program to respond (this may take a few seconds)

Step 4: Check the results

Look at what appears in the black window: