Outlook Login Problems

Fix Outlook for Mac Sign-In Loop After macOS Sonoma Upgrade

Natalie Taylor Oct 10, 2026 869 views

Question details

The user is experiencing a continuous sign-in loop in Outlook for Mac, and other Microsoft Office applications are locked in a read-only state after upgrading to macOS Sonoma.

Fix Outlook for Mac Sign-In Loop After macOS Sonoma Upgrade

Product: Outlook for Mac / Microsoft Office
Device & OS: macOS Sonoma
Scenario: Attempting to log into Outlook and edit documents in other Office applications following a macOS system upgrade.
Observed behavior: Outlook repeatedly returns to the password screen even after successful authentication and two-factor verification. Other Office applications remain in read-only mode, and reinstalling Office or clearing keychain data has not resolved the issue.

Before you start

Ensure you have your Microsoft account credentials ready and do not delete your existing macOS user profile to avoid permanent data loss during testing.

Solution 1Recommended

Test the Account in Legacy Outlook

Switching to the legacy version of Outlook can often bypass new authentication bugs present in the updated interface.

The New Outlook for Mac utilizes a different sync technology that can sometimes conflict with macOS keychain updates, leading to verification loops.

Open Outlook

Launch the Outlook for Mac application on your computer.

Revert to Legacy Mode

Click on the 'Outlook' menu at the top left of your screen and uncheck 'New Outlook', or navigate to the 'Help' menu and select 'Revert to Legacy Outlook'.

Sign In Again

Enter your credentials and complete the two-factor authentication to see if the continuous loop persists in the older interface.

Temporary Workaround: If Legacy Outlook works, you can continue using it while Microsoft releases a permanent patch for the New Outlook authentication bug on macOS Sonoma.

Solution 2

Create a Separate macOS User Profile

Testing Office applications in a fresh macOS user profile helps determine if your original profile's authentication data is deeply corrupted.

Free Microsoft Office alternative

Try WPS Office as a Reliable Mac Alternative

If your Microsoft Office apps are stuck in a frustrating read-only mode due to unresolved authentication loops, WPS Office provides a free, lightweight, and fully compatible alternative to keep you productive on macOS.

1. Download WPS Office: Visit the official WPS website and download the free macOS installation package.
2. Install the Application: Open the downloaded file and drag the WPS Office icon into your Applications folder.
3. Edit Your Files: Launch WPS Office and directly open your existing Office documents to resume editing without any read-only restrictions.

Free and lightweight Office suite tailored for macOSHighly compatible with Microsoft Word, Excel, and PowerPoint formatsNo complex subscription sign-in loops or read-only lockoutsFamiliar user interface for a seamless and quick transition

microsoft office alternative - wps office

Frequently Asked Questions

Why are my Office apps in read-only mode after the macOS Sonoma update?

This typically happens when Office fails to verify your Microsoft 365 subscription status due to corrupted keychain credentials or a continuous sign-in loop. Without verification, the apps restrict your access to read-only mode to protect against unlicensed usage.

Will I lose my emails if I switch back to Legacy Outlook?

No, switching to Legacy Outlook only changes the user interface and the underlying sync protocol. Your emails, contacts, and calendar events remain safely stored on your email provider's servers.

How do I manually clear corrupted keychain data for Office on Mac?

Open the 'Keychain Access' app on your Mac, search for keywords like 'Microsoft Office', 'ADAL', or 'Exchange', and delete the associated password entries. Restart your Mac and try signing into Office again.

Outlook & Email Problems