File Format & Compatibility

How to Fix Excel Not Saving Changes or Formatting After an Update

Huma Ashraf Ch Oct 1, 2026 868 views

Question details

The user is experiencing data loss and missing formatting in Excel workbooks after saving and reopening files, specifically following an Office 2021 update.

How to Fix Excel Not Saving Changes or Formatting After an Update

Product: Microsoft Excel 2021
Device & OS: not provided
Scenario: Saving a workbook after making data updates and formatting adjustments.
Observed behavior: Formatting and recent data changes disappear entirely after the workbook is saved and reopened.

Before you start

Before attempting any fixes, create a duplicate copy of your current workbook and save it in a safe location to prevent further data loss.

Solution 1Recommended

Save the Workbook in XLSX Format

Ensure your file is saved as a standard Excel Workbook (XLSX) rather than a CSV, as CSV files cannot store formatting.

CSV (Comma Separated Values) format stores only plain text. If you save a formatted workbook as a CSV, all cell colors, fonts, column widths, and formulas will be discarded upon closing the file.

Additionally, manually renaming a file extension from .csv to .xlsx in your system files does not convert the format properly and can lead to unreadable files.

Open the Save As Menu

Open your problematic workbook in Excel and click on the 'File' tab in the top left corner, then select 'Save As'.

Select the Correct Format

Click the 'Save as type' dropdown menu below the file name field and select 'Excel Workbook (*.xlsx)' from the list of options.

Save the Converted File

Click the 'Save' button. Any new formatting or data changes you make to this newly saved file will now be preserved correctly.

Avoid Manual Extension Changes: Never manually change the file extension in your computer's file explorer. Always use the 'Save As' function within the application to convert file types.

Solution 2

Repair Your Microsoft Office Installation

If the issue persists and involves error messages when saving, repairing Office can resolve glitches introduced by the recent update.

Free Microsoft Office alternative

Avoid Update Glitches with WPS Office

Tired of missing formatting and lost data after unexpected Microsoft Office updates? WPS Office is a free, lightweight, and highly stable alternative that protects your work and offers full file format compatibility.

1. Download and Install: Visit the official WPS Office website to download and install the free software on your device.
2. Open Your File: Launch WPS Spreadsheets and open your existing Excel (.xlsx or .csv) files directly without any conversion.
3. Save Securely: Make your changes and simply click Save. WPS Office natively preserves all formatting seamlessly.

100% compatible with Microsoft Excel formats including .xlsx, .xls, and .csvNo forced background updates that disrupt your workflow or corrupt your saved filesLightweight installation ensures fast loading and highly responsive saving processesFamiliar spreadsheet interface requires zero learning curve to make the switch

microsoft office alternative - wps office

Frequently Asked Questions

Why did my formatting disappear after saving in Excel?

If your file was originally saved as a CSV (Comma Separated Values), Excel will drop all formatting upon closing. CSV files only support raw text data. Always use 'Save As' and select XLSX to preserve fonts, colors, and layouts.

Can I manually rename a .csv extension to .xlsx?

No, renaming the file extension in your operating system does not change the file's internal structure. Doing so can cause file corruption. You must open the file in Excel and use the 'Save As' menu to properly convert it to an Excel Workbook.

Does updating Office automatically change my default save format?

Updates should not change your default save format, but they can occasionally cause application glitches or reset preferences. If your default format changed to CSV, go to Excel Options > Save, and ensure 'Save files in this format' is set to Excel Workbook (*.xlsx).

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