Sub-Workflow does not complete run

Questions
1

Describe the problem/error/question

I have a main workflow (see Screenshot 1) that calls two sub-workflows. The second sub-workflow takes quite a while to complete, and I do not need its output in the main workflow. It should just be triggered and run independently.

To achieve this, I disabled “Wait For Sub-Workflow Completion” (see Screenshot 2). However, this causes unexpected behavior:

The sub-workflow gets triggered but finishes immediately without actually running (see Screenshot 3). The trigger node receives the data and reports a success status, but the workflow itself does not continue executing.

If I enable “Wait For Sub-Workflow Completion”, the sub-workflow runs correctly — but this blocks the further execution of the main workflow, which I want to avoid.

Main Workflow
Main Workflow628×388 34.4 KB

Setting Sub-Workflow Trigger
Setting Sub-Workflow Trigger671×471 25.8 KB

Sub-Workflow Run
Sub-Workflow Run748×253 26.4 KB

I expected that with “Wait For Sub-Workflow Completion” disabled, the sub-workflow would still run in the background, even if the main workflow doesn’t wait for it and is already completed. Essentially, a fire-and-forget behavior.

  • Is this expected behavior?
  • Is there another way to start a sub-workflow without waiting for it, but ensuring it actually runs? (despite calling it via a webhook)?

Information on your n8n setup

  • n8n version: 1.93.0
  • Database (default: SQLite): default
  • n8n EXECUTIONS_PROCESS setting (default: own, main): default
  • Running n8n via (Docker, npm, n8n cloud, desktop app): n8n cloud
  • Operating system:
2

Hey @jonas_py,

I created a sample workflow to test the behavior you mentioned in your post. I disabled the “Wait for Sub-Workflow to Finish” option and found that everything worked as expected. Based on this, it seems like the issue you’re experiencing is not typical behavior.

I’d recommend taking another look at your workflow. Personally, I’ve run into similar issues before, only to realize later that I had made a small mistake. I’m not suggesting that’s necessarily the case here, but it’s definitely worth double-checking.

If it’s still not working as expected, you could try an alternative approach:

  • Use a Webhook node to trigger the sub-workflow and make sure the sub-workflow is set to active.
  • Then, from your main workflow, use an HTTP Request node to call the sub-workflow’s webhook URL.

Make sure that in the sub-workflow’s Webhook node, the “Respond Immediately” option is enabled. This way, the main workflow will trigger the sub-workflow without waiting for it to finish.

Let me know if this helps.

3

Hey @Sudhanshu_Sharma,

Thanks for the quick response and testing it on your side.

I followed your advice to check it again, deleting the trigger sub-workflow node and adding it again in the main workflow did the job. Now it is working.

Thanks! Have a great evening.