Hey is anyone getting a similar error. I have done all of the n8n AI suggested fixes (refreshing column lists, etc.) and have checked the columns and I cannot see why the mapping in the error is incorrect, vs what it is on the column mapping. Genuinely no idea how to solve this.
Describe the problem/error/question
What is the error message (if any)?
Please share your workflow
(Select the nodes on your canvas and use the keyboard shortcuts CMD+C/CTRL+C and CMD+V/CTRL+V to copy and paste the workflow.)
hello @jamiemcc
That issue usually happens with the Google Sheet node when there are some updates in the sheets. You’ll need to refresh the column for the changes to take effect. It’s more about fields reordering.
this error with the Google Sheets node almost always shows up after the sheet structure changed (columns added/removed/renamed, header row edited, or even columns reordered), and n8n is still using a stale column schema from when the node was first configured. Refreshing columns helps, but if it still doesn’t, what I do is to make sure the header row is exactly one clean row (no merged cells, no blank header names, no duplicate header names), confirm the node is pointing to the correct sheet/tab and the correct header row, then reselect the target column fields again after refresh. If it keeps failing, the fastest “hard reset” is to duplicate the Google Sheets node (or delete + re-add it) and remap from scratch, that forces n8n to pull the latest schema cleanly.
One thing that catches people out is if the sheet name itself changed or if you’re pointing at a different tab than you think you are. Also worth checking if there’s any whitespace in your header names that looks invisible but isn’t matching, sometimes copying from somewhere else introduces weird characters. If you’ve genuinely tried refreshing columns and it still complains, try deleting the Google Sheets node entirely and adding a fresh one, re-authenticate and re-select the sheet from scratch. Annoying but it forces n8n to grab a completely clean schema.
Please take a screenshot to your node, however there are two probabilities : First you should map the columns manually if you have already set up your columns on your google sheet, Second if you haven’t and you would like the AI Agent to map them for you, then you don’t need a column to match on.
The tab in the sheet i am appending to has 5 header rows and has certain column header names duplicated , depending on the sub-section it sits under (ERP template’s standard format) and I wonder is this causing issues?
Also, the sheet where the tab lives has been appended to in a number of nodes in my workflow prior to arriving at this final step - so I wonder is that resulting in perseived update of the headers - where I don’t see where this occured.
Issue with the columns;
I think the duplicated column name (External Supplier Invoice Source) may be causing the schema to get confused? Would this by why it is happening?
Screenshot 1 (mapping on n8n - only 1 External Supplier Invoice Source)
Screenshot 2 (headers on the sheet - 2 External Supplier Invoice Source columns
Yeah that’s definitely it, the duplicate column names are confusing the schema lookup. Google Sheets node can’t distinguish between two columns with the same header so it just grabs whichever one it finds first and the mapping gets scrambled. With 5 header rows and duplicates you’re kind of fighting the node’s design, it really expects one clean header row with unique names. If you can’t change the ERP template you might need to use the HTTP Request node with the Sheets API directly and handle the row/column targeting yourself.
