Symptom

  • When starting ComfyUI, multiple lines of (IMPORT FAILED) appear in the terminal, and specific custom nodes cannot be used or do not appear in the node list.

Timing of occurrence

  • Immediately after starting ComfyUI.
  • When installed custom nodes do not appear in the node list.

Cause

  • Essential libraries are missing, or an incompatible Python / PyTorch version is used.
    • If you scroll up from (IMPORT FAILED) in the terminal, you will see ModuleNotFoundError: No module named 'facenet_pytorch', etc., indicating that the library required for that custom node cannot be found.
  • Path or OS dependent issues.
    • Example: Cases like UnicodeDecodeError('cp932' codec can't decode byte 0x87...) where having non-ASCII characters in the folder path causes errors.
  • Conflict with other custom nodes.
    • Sometimes nodes with old frontend implementations or unique dependencies crash because they are incompatible with the new ComfyUI.

Solution

  • If libraries are missing

    • If you are familiar with Python, you can pip install yourself, but otherwise, first open the GitHub of that custom node and check if the installation method is correct.
    • Currently, if it is via ComfyUI Manager, many nodes install necessary libraries all together. Unless there is a special reason, please install from Manager first.
    • Even for nodes where special procedures like "Please run this script manually" are written in README, if you don't understand well, please do not touch it in the first place.

  • If conflict with other custom nodes is suspected

    • If possible, evacuate custom nodes other than the one outputting (IMPORT FAILED) from custom_nodes, and check if ComfyUI starts with only that node remaining.
    • After that, return them little by little in combinations of "problem node + one other node" to isolate which node causes the crash when combined.
    • If you don't need to use it that much, uninstall that node (delete the folder itself).