Which transformations break query folding?

< 1 min read

Certain steps force Power Query to process data locally instead of pushing to source.
Adding Index column usually breaks folding because database cannot guarantee row order.
Using custom columns with M functions (Text.Proper, Date.MonthName etc.) often stops folding.
Merging with non-database sources like Excel/CSV breaks folding immediately.
Changing column data types sometimes breaks folding depending on connector.
Pivot / Unpivot and Group By on unsupported sources also stop folding.
Invoking custom functions or row-by-row logic definitely breaks it.
Sorting after certain steps can also disable native query.
In projects, I keep filters & column removal first and complex logic last to preserve folding.

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