No Output from Execute Workflow Node in Loop Over Items After First Iteration

Hello, n8n community,

I’m encountering a problem while working with a Loop Over Items node, where I aim to execute an Execute Workflow node multiple times using different item data each time. My goal is to capture and retain the output from each execution for use in subsequent iterations within the loop.

Expected Behavior: Each iteration through the Execute Workflow node within the loop should yield output, which I can then use in the next iteration.

Current Issue: The first iteration through the Execute Workflow node produces output as expected. However, in the second iteration, there is no output from the Execute Workflow node, which causes the process to stall.

Has anyone encountered a similar issue or can provide insight into what might be going wrong? Any suggestions or solutions to ensure consistent output from each iteration would be greatly appreciated.

Thank you in advance for your help!

Output returned by the vital node

My workflow overview, problem related part in red rectangular:

First iteraion on Execute Workflow Node:

Second iteraion on Execute Workflow Node:

Sub-workflow executions, both of the Requests successed and have expected outputs:

Information on your n8n setup

  • n8n version: 1.36.0
  • Database (default: SQLite): SQLite
  • Running n8n via (Docker, npm, n8n cloud, desktop app): Docker

It sounds like you misunderstood how Loop works or I misunderstood your statement. Loop node allows you to batch your data. Once an item iterated once, the ourcome of that iteration comes out of the “done” output. That is, you cannot iterate the same item second time in the same loop. Schematically, it works like this.

However, Done node will get the result when all the (batched) items have been processed (once). If at any point the loop breaks, you will get no (done) output. Having conditional checks in the loop is the typical reason for breaking the loop. For the loop to succeed, you have to have an output from Process node to be pushed to the input of Loop node. This output will end up as the output of Done node.

My apologies for the unclear explanation before. I anticipated that running successive items through the Execute Workflow node would each produce an output, but in my scenario, there’s no output after the second execution and causing the workflow to stall.

@Lyus , to fix it, you can try setting the node returning no output (and subsequent if there are any) to always return a value.

This setting can make loop go on, but it’ll output empty for the second iteration on this node and some of the successive nodes will use the Execute Workflow Node output, so this not solve the problem of outputing the sub-workflow execute output.