Power Query Refresh loading unused file, saying size is multiple times its actual size

Hi LYorkToenniges ,

Thanks for reaching out to the Microsoft Fabric Community, and for sharing the additional details.

From what you described, this behavior aligns with how Power Query evaluates queries rather than an unrelated file being loaded.

Power Query may evaluate the same data source multiple times. If a file is referenced anywhere in the model, especially through referenced queries, it can be evaluated repeatedly during refresh. For example, if multiple queries reference the same source, it may be executed multiple times rather than once and shared.

This is documented here:
Why does my query run multiple times - Power Query | Microsoft Learn
Solved: Re: loading the source several times - Microsoft Fabric Community

In this setup, even if a base query (such as the one pointing to your Excel file) is not loaded, it can still be re-evaluated when another query depends on it. This can make it appear as if an unrelated file is being loaded.

Also, Excel sources do not support query folding, so transformations are processed within Power Query. This can increase in-memory processing and is one of the reasons you may see the size during refresh appearing larger than the actual file size.

Regarding your expectation that only a single sheet should be read, the Excel.Workbook function first retrieves the workbook structure (all sheets/tables/metadata), and filtering to a specific sheet is applied afterward.

Given this, it would be helpful to confirm whether that file is used anywhere else in the model, even indirectly (for example through another query). If so, the behavior you are seeing would be expected.

If the same behavior occurs with a fully isolated query, feel free to share a simplified version of the query structure and we can take a closer look.

Hope this helps. Please reach out for further assistance.
Thank you.