After hundreds of remote fix sessions, these are the errors that come up again and again.
When a workflow breaks, most people guess. Here's the systematic decision tree we use in real support sessions.
买了 5070 Ti / 5080 / 5090，ComfyUI 装不上？这里是原因和解决方案。
Your GPU is there, but ComfyUI refuses to use it. Here's every reason torch.cuda.is_available() returns False.
ComfyUI plugins fight over numpy, pillow, and torch versions. Here's a real-world guide to finding and fixing dependency hell without nuking your environment.