Microsoft 365 Error Codes

How to Fix Excel Session Expired Error in Microsoft 365

Maira Mehtab Sep 21, 2026 869 views

Question details

Users encounter a 'Session Expired' error shortly after opening an Excel file in Microsoft 365, which forces the file to close or blocks further editing.

Product: Microsoft 365 Excel
Device & OS: not provided
Scenario: Opening and editing an Excel file connected to Microsoft 365 cloud services.
Observed behavior: A Session Expired error appears within a minute of opening the file, preventing the user from continuing to edit and sometimes closing the file automatically.

Before you start

Ensure you have a stable internet connection and try saving any unsaved work locally to a different folder before logging out, as session errors can lead to data loss if cloud syncing fails.

Solution 1Recommended

Sign Out and Re-authenticate Your Microsoft 365 Account

Refreshing your account session by signing out and signing back in is the most effective way to resolve temporary authentication token expiration errors.

The 'Session Expired' error usually occurs when the authentication token between your desktop application and Microsoft's cloud services becomes invalid or expires.

Open Account Settings

Launch Microsoft Excel. Click on 'File' in the top-left corner, then select 'Account' from the bottom-left menu.

Sign Out

Under the 'User Information' section, click the 'Sign out' button. If you have multiple accounts connected, sign out of all of them.

Restart and Sign In

Close Excel completely, then reopen the application. Navigate back to 'File' > 'Account' and click 'Sign In' to re-enter your Microsoft 365 credentials.

Authentication Refreshed: Once signed back in, your session token will be renewed, and cloud-connected files should open without triggering the expiration error.

Solution 2

Clear Office Cached Credentials in Windows

If signing out doesn't work, clearing corrupted Windows credentials related to Office can force a clean connection to Microsoft 365.

Solution 3

Check Microsoft 365 Service Status

Verify if the issue is caused by a widespread server outage on Microsoft's end rather than a local configuration problem.

Free Microsoft Office alternative

Edit Spreadsheets Offline with WPS Office

Tired of dealing with Microsoft 365 cloud session errors? Try WPS Office. It provides robust offline editing capabilities without frustrating session timeouts, while remaining fully compatible with your existing Microsoft Excel files.

1. Install the Software: Download and install the free version of WPS Office on your PC or Mac.
2. Open Your File: Launch WPS Spreadsheets, click 'Open', and select your existing .xlsx file to continue working without session timeouts.
3. Save Locally or to Cloud: Edit your document freely and save it locally to your hard drive or to a stable cloud service of your choice.

No cloud session expiration interruptions during local offline editing.Fully compatible with Microsoft Excel (.xls, .xlsx) formats.Lightweight software that loads quickly on any desktop or mobile device.Free to use with a familiar, easy-to-navigate interface for seamless migration.

microsoft office alternative - wps office

Frequently Asked Questions

Why does Microsoft 365 keep saying my session has expired?

This typically happens when your authentication token expires, your account password was recently changed on another device, or there is a synchronization issue between your desktop Excel app and Microsoft's cloud servers.

Can I recover unsaved data if Excel closes due to a session error?

If AutoSave was active before the session expired, your changes might be safely synced to OneDrive or SharePoint. You can also check the Document Recovery pane by reopening Excel immediately after the crash.

Does the session expired error happen in offline mode?

No, the 'Session Expired' error is exclusively triggered by cloud-connected features like AutoSave to OneDrive, SharePoint co-authoring, or when using Excel for the Web.

Microsoft Office Error Codes