You open ComfyUI and suddenly see “Reconnecting” on the screen. It stops your workflow or image generation.
When this happens, your browser loses connection with the backend running on Python, but sometimes your system or network causes it too. This guide explains what it means, why it happens, how to fix it step by step, and how to stop it from happening again.
What Is the ComfyUI Reconnecting Error?
The reconnecting error means the browser UI cannot stay connected to the ComfyUI backend. The backend runs through Python and handles tasks like loading models, running nodes, and processing images. When you click run, the system sends a request using a WebSocket connection through localhost, often 127.0.0.1.
If that connection breaks because of a crash, memory issue, or blocked communication, the UI shows “Reconnecting” and keeps trying to restore the link.
This usually happens during heavy tasks like loading checkpoints, running KSampler, or processing large workflows with high VRAM use.
You usually see this message during queue execution, model loading, or after clicking run. It may appear suddenly while using nodes, especially when working with GPU-heavy tasks on Windows 11 or Windows 10. The message itself is simple, but it often means the backend stopped responding.
Common Causes of the ComfyUI Reconnecting Error
This error can happen for several reasons depending on your system, setup, and workflow.
- GPU VRAM runs out during model loading or sampling
- System RAM or page file is too low
- Broken or conflicting custom nodes
- Version mismatch in PyTorch, CUDA, or Python
- GPU driver crash or backend process failure
- Firewall or antivirus blocking localhost connection
- Browser WebSocket disconnect or tab issue
How to Fix the ComfyUI Reconnecting Error?
To resolve this issue efficiently, you need to check both your system resources and your setup. However, most fixes are simple once you find the real cause.
Fix #1: Check the Terminal or Log First
This error often shows up after a backend crash. The terminal window gives you the real reason.
Follow the steps below to easily check logs.
- Open the ComfyUI terminal window
- Look at the last error message
- Check for VRAM, CUDA, or node errors
- Note any crash or warning lines
- Use that info to guide your fix
Fix #2: Reduce VRAM and RAM Usage
Heavy workflows can overload your GPU or system memory. When VRAM runs out, the backend may crash and cause reconnecting. Lowering resolution, batch size, or using smaller models helps reduce pressure on your system and keeps ComfyUI stable.
Fix #3: Disable Custom Nodes
Custom nodes can break after updates or conflict with each other.
You can perform the following steps to disable custom nodes.
- Go to your ComfyUI folder
- Open custom_nodes directory
- Temporarily move nodes out
- Restart ComfyUI
- Test with default setup
Fix #4: Try a Basic Workflow
Sometimes the problem is not ComfyUI itself but your workflow. Running a simple setup like SD 1.5 text-to-image helps test if your system is stable. If the simple workflow works, then the issue likely comes from a complex node or model.
Fix #5: Check Python, PyTorch, and CUDA
Version mismatch can cause backend failure.
Here are the following steps which help you to check compatibility.
- Check your Python version
- Verify PyTorch version
- Confirm CUDA matches your GPU
- Update or reinstall if needed
- Restart ComfyUI
Fix #6: Update or Roll Back Drivers
GPU drivers can sometimes cause crashes. If the error started after a driver update, rolling back may help. If your drivers are outdated, updating them can fix compatibility problems and improve stability.
Fix #7: Check Firewall, Antivirus, or VPN
Security tools can block localhost communication. ComfyUI uses local connections like 127.0.0.1, and if your firewall or VPN interferes, the browser loses connection. Disabling these temporarily helps confirm if they are causing the issue.
Fix #8: Reinstall ComfyUI Cleanly
If nothing works, reinstalling ComfyUI may fix deeper issues. A clean setup removes broken dependencies, resets your environment, and ensures everything works correctly. It takes time, but it solves many persistent problems.
Is the Reconnecting Error a Crash or Just a Connection Issue?
In most cases, this error means the backend has crashed. When your GPU runs out of VRAM, or a node fails, the backend process stops working, and the browser keeps trying to reconnect. This is common when running heavy models or complex workflows.
However, sometimes it is only a connection issue. A browser refresh, network hiccup, or blocked WebSocket can cause temporary disconnects without a crash. In those cases, the system reconnects quickly, and your workflow may continue.
Prevention Tips to Avoid the ComfyUI Reconnecting Error
Taking a few simple steps can help you avoid this error in the future.
- Keep custom nodes updated carefully
- Test new nodes one at a time
- Monitor VRAM and RAM usage
- Keep GPU drivers stable
- Avoid unnecessary VPN or proxy tools
- Use simple workflows when testing
- Back up a working setup before updates
Conclusion
The ComfyUI reconnecting error usually means your browser lost connection with the backend. It often happens because of memory limits, custom node issues, or system conflicts, especially when running heavy workflows or large models.
Start by checking logs, then try fixes one by one. If the issue continues, share your logs with the community or support forums. If this guide helped you, share it or leave a comment so others can fix the same problem faster.
