Check XLSX worksheets and formulas before cleanup

Step-by-step approach

1. Keep the original workbook intact.
2. Open the XLSX Worksheet Inspector to see available sheet names and formula counts.
3. Identify hidden or calculation-heavy sheets that cannot be represented in simple CSV.
4. Verify cached values in your spreadsheet software before relying on exported results.
5. Save a new file and document omitted workbook features.

What this does not solve

Browser tools can validate known structures and transform available data, but cannot restore deleted or corrupted bytes, infer unknown business facts, or guarantee that a target system will import every field as intended.