File Format & Compatibility

How to Fix Microsoft Forms Update File Format and Sync Errors

Huma Ashraf Ch Sep 27, 2026 869 views

Question details

The user needs to resolve an issue where Microsoft Forms cannot update a response workbook and displays an 'Update file format' error, despite the file already being in the .xlsx format.

Fix Microsoft Forms Update File Format and Sync Errors

Product: Microsoft Forms
Device & OS: not provided
Scenario: Syncing new form responses to an existing Excel workbook.
Observed behavior: Microsoft Forms repeatedly shows an 'Update file format' error and stops syncing data to the connected Excel file, even after confirming the file is saved as an .xlsx workbook.

Before you start

Verify that your Microsoft 365 subscription is active and ensure you have administrator privileges, as resolving persistent server-side sync issues may require opening a backend support ticket.

Solution 1Recommended

Disconnect and Synchronize Responses to a New Workbook

This solution forces Microsoft Forms to create a fresh connection by syncing the form responses to a completely new Excel workbook.

Often, the connection between Microsoft Forms and the specific Excel file gets corrupted. Creating a new workbook forces the system to generate a clean .xlsx file, bypassing the false file format error.

Verify Current File Format

Open your Microsoft 365 account, navigate to Excel for the web, and verify that the current response workbook is indeed saved in the .xlsx format.

Disconnect the Existing Workbook

Go to Microsoft Forms, open the affected form, navigate to the 'Responses' tab, click the 'More options' (three dots) icon, and select the option to disconnect the current workbook.

Sync to a New Workbook

In the same 'Responses' tab, click 'Open in Excel' to synchronize the collected responses to a newly generated .xlsx workbook.

Disconnect and Synchronize Responses to a New Workbook

Data Safety: Disconnecting the workbook does not delete your form responses. The data is safely stored in the Forms web app and will fully populate the new workbook once synced.

Solution 2

Escalate to Microsoft 365 Support

If disconnecting the workbook does not resolve the error, the problem is likely a server-side glitch requiring Microsoft's backend intervention.

Free Microsoft Office alternative

Use WPS Office to Analyze Your Exported Form Data

Since Microsoft Forms sync errors are often tied to Microsoft's server backend, you cannot fix them directly. However, once you download your responses as an offline .xlsx file, you can manage and analyze your data seamlessly with WPS Office—a fast, free, and highly compatible alternative to Microsoft Office.

1. Download WPS Office: Visit the official WPS Office website and download the free installation package for your device.
2. Install the Software: Run the installer and follow the on-screen instructions to complete the setup in minutes.
3. Open Your Data: Launch WPS Spreadsheets and open the downloaded .xlsx Forms response file to start analyzing your data.

100% compatible with Microsoft Excel (.xlsx, .xls) formatsLightweight application that loads large datasets quicklyFree to use with a familiar, easy-to-learn interfaceBuilt-in tools for data filtering, charts, and PDF conversion

Frequently Asked Questions

Why does Microsoft Forms show a file format error for an .xlsx file?

This usually happens due to a server-side synchronization glitch or an interrupted connection between the Forms web app and Excel for the web, causing Forms to misread the file's properties.

Will I lose my responses if the Excel sync fails?

No. The responses are securely stored within the Microsoft Forms web app. You can always view them there or generate a new Excel workbook to export the data.

How do I download a static copy of my form responses?

If live syncing is broken, you can go to the Responses tab in Microsoft Forms, click the three dots, and choose to download a copy of all current responses as an offline Excel file.

Document & File Issues