ComfyUI workflow save failed: preserve the canvas before troubleshooting

Preserve the work first

If the canvas contains unsaved changes, our first recommendation is to stop refreshing or clearing storage. Where the current UI allows it, use the regular workflow Export action to download the canvas JSON. Confirm the file exists, then copy or rename it to a separate backup location before further experiments; the suggested download name may reuse the current workflow name. If export fails too, keep the tab open while gathering evidence. Menu labels vary by version.14

Distinguish a server-stored workflow, a downloaded workflow JSON file and an API-format export. The frontend offers regular Export and Export (API) as separate formats; the API output is not a substitute for a verified canvas backup. One successful operation does not validate the others. The server API documentation provides context for the service side.2

Investigate a small reproduction

Once a copy is safe, record the failing save request in the Network panel.3 Preserve its method, path and response. Do not assume a Python dependency is responsible for a browser download failure.

After a separate backup exists, try a small non-private workflow under a new name. Reopen the downloaded workflow JSON in a separate tab or test instance, then separately verify that a server-side save can be read back. Keep the original complex workflow untouched while testing.

A useful report includes frontend version, save action, export availability and the failing request. A screenshot documents the UI but is not a recoverable workflow backup.

Related checks

• ComfyUI Failed to fetch: identify the request before reinstalling
• Keep a reproducible ComfyUI repair record without exposing secrets

Source and language review: 2026-09-26. No site-run save failure, browser recovery, workflow execution or GPU test is claimed. The recovery sequence is editorial guidance, not a confirmed fix.