How can I resolve merge node input conflicts to process binary chat data in my n8n workflow?

Below is some guidance based on our documentation on similar scenarios:

What’s Happening

When the “Extract from PDF” node outputs content (true branch) the merge node only receives an item from “Input 2” (e.g. the chat binary data). In your workflow the merge node has been designed (in legacy workflows this behavior is common) to wait for both inputs to be available before outputting data. In your case Input 1 isn’t executed at all when there is content, so the merge node never completes its merging step—resulting in no final output for your chat.

Why It’s Not a Misconfiguration

The merge node isn’t misconfigured per se. The behavior you’re seeing is related to how branches are handled within your workflow. In legacy execution modes (or if your design expects both branches to always provide data) the merge node may wait on an input that isn’t coming. Even though you only need the binary chat data for the false branch, if the true branch is taken then the merge node’s other input remains empty.

How to Fix It

You have a few options:

1. Use “Choose Branch” Mode Instead:
   Instead of a standard merge mode, switch the merge node to the “Choose Branch” (or “Choose Input”) mode. This option always waits for data from both inputs but then picks the output from a selected input. You would configure it to output from Input 2 (your chat data) when the false branch is active. This way, if the true branch is activated (extract has content) the merge node won’t wait on an empty input.

2. Ensure Both Inputs Always Output Something:
   If you prefer to keep your merge mode as is, add an intermediate node (for example, an Edit/Set node) on the branch that would otherwise have no output (i.e. when “Extract from PDF” has content) to send a dummy or empty item. This lets the merge node know that Input 1 has “completed” even if it’s just an empty value—allowing it to finish execution and output the data from Input 2.

3. Reconsider the Workflow Design:
   Since you only need binary chat data when “Has content” is false, you might adjust your workflow to route the false branch directly to your chat node. This way you avoid merging branches that aren’t both required. For example, use an If node to decide which branch should be processed and then send only that branch’s data forward.

Final Thoughts

Double-check your workflow’s execution order in the settings (n8n 1.76.1 should default to the new execution order, not legacy) and adjust the merge node options accordingly. The key is to always provide a value for the input you expect to merge or to pick a merge mode (like “Choose Branch”) that lets you select the branch you need.

This should resolve the issue where the chat stays waiting for content from an input that isn’t run in the true branch scenario.