Hello @martymwas
This error typically means that one of the columns in your Power Query still contains a nested value (a Table or Record), but a later step is trying to treat it as Text. In Dataflows Gen2 loading into a Fabric Lakehouse, this often shows up during the insert step as Lakehouse036. The most common causes are unexpanded columns after a Merge (Join) or Group By (All Rows), or an auto-generated Changed Type step that attempts to coerce a nested column to text.
To identify the issue, step back to the transformation just before the failure and inspect column data types. Look for columns showing as Table or Record in the profile. In many cases, simply expanding the merged/grouped column before applying text operations or type changes resolves the problem. Be especially cautious with blanket Changed Type steps, as these frequently introduce the error.
As a diagnostic approach, you can also add a temporary step to flag rows or columns that contain tables or records, helping pinpoint the exact source. In general, the correct fix is to expand and normalise nested structures rather than attempting to convert them to text, unless you explicitly intend to serialise them (e.g. to JSON).
I trust this will be helpful. If you found this guidance useful, you are welcome to acknowledge with a Kudos or by marking it as a Solution.
