Windows
Excel formatting changes were not being retained because the file was a .csv
Excel was opening a comma-separated values (.csv) file, so formatting changes were not being preserved. The file was saved as an Excel workbook (.xlsx) and the formatting changes then saved correctly.
Killed once by someone from XL.net, on 2025-12-15.
Affects
Versions
- Windows
Apps
- Excel
What you see
- Changes appeared to save, but the file reverted to the original content after reopening.
- Formatting changes would not stick while the file was in .csv format.
Why it happens
Likely The file was a comma-separated values (.csv) file, which stores values but not formatting.
When it shows up
An Excel file is actually a .csv file and formatting changes are not being preserved after save.
You are in this case if:
- The file extension is .csv.
- Excel shows the document as a comma-separated values file.
- Formatting changes disappear after the file is saved and reopened.
1 fix below
The steps that killed it
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Keeping it away
- Use .xlsx when the file needs to keep formatting or other Excel-only features.
Someone from XL.net killed this on a Windows computer on 2025-12-15. It is written up from that one repair, so it cites no outside page.