Sign-in & Login Problems

Fix Cannot Sign In to Microsoft 365 Apps on MacBook

Nimra Malik Oct 10, 2026 869 views

Question details

The user is unable to sign in to Microsoft 365 desktop applications on a MacBook, despite having an active subscription and successfully logging in on the Microsoft website.

How to Fix Microsoft 365 App Sign-In Issues on a MacBook

Product: Microsoft 365 / Office for Mac
Device & OS: macOS Monterey
Scenario: Attempting to activate and use Microsoft Office applications on a Mac using a Microsoft 365 Family subscription.
Observed behavior: The Office sign-in window loops repeatedly without prompting for a password, or displays an error stating that the Microsoft account does not exist.

Before you start

Verify that your Mac is connected to a stable network, and ensure you are entering the exact email address associated with your active Microsoft 365 subscription.

Solution 1Recommended

Clear Office Credentials from Keychain Access

Use this method if the app keeps looping back to the login screen or fails to recognize your account. Clearing cached credentials forces Office to authenticate freshly from the server.

macOS stores application login tokens in a secure utility called Keychain Access. Sometimes, outdated or corrupted authentication tokens prevent Microsoft Office apps from connecting to Microsoft's servers, causing an infinite login loop or false 'account does not exist' errors.

Close all Office Applications

Ensure that Word, Excel, PowerPoint, and Outlook are completely closed on your MacBook.

Open Keychain Access

Go to Finder > Applications > Utilities, and double-click 'Keychain Access' to launch the application.

Delete Microsoft Office Entries

In the top right search bar of Keychain Access, type 'Microsoft Office'. Select all matching items (such as 'Microsoft Office Identities Cache' and 'Microsoft Office Identities Settings'), right-click them, and click 'Delete'.

Restart and Sign In

Restart your MacBook. Open any Microsoft Office application, click 'Sign In', and enter your Microsoft 365 credentials.

Clear Office Credentials from Keychain Access

Safe Procedure: Deleting these Keychain entries will not delete your documents or local files; it only removes saved login sessions.

Solution 2

Update macOS and Reinstall Microsoft 365

If clearing the Keychain does not work, the issue may stem from an outdated operating system or corrupted Office installation files.

Free Microsoft Office alternative

Try WPS Office for Mac – A Lightweight & Free Alternative

If you are tired of frustrating Microsoft 365 activation loops and sign-in errors, WPS Office provides a seamless, familiar interface for your documents without the subscription hassles. It runs flawlessly on macOS and lets you edit your files immediately.

1. Download WPS Office: Visit the WPS Office website and download the macOS version.
2. Install the Application: Open the downloaded .dmg file and drag the WPS Office icon to your Applications folder.
3. Start Editing Instantly: Launch WPS Office and open your existing Word, Excel, or PowerPoint files without needing a complex sign-in process.

Fully compatible with Microsoft Office formats including .docx, .xlsx, and .pptx.Lightweight design that runs smoothly on Mac without draining system resources.No complex activation loops or forced cloud sign-ins to edit your local files.Free to use for basic document, spreadsheet, and presentation tasks.

Frequently Asked Questions

Why does Microsoft 365 say my account doesn't exist on Mac but works online?

This usually happens due to corrupted or outdated login tokens stored in your Mac's Keychain. The web browser uses a different authentication method, which is why it continues to work while the desktop apps fail.

Will removing Keychain access passwords delete my documents?

No. Deleting Microsoft Office entries in Keychain Access only removes the saved login data. Your local documents and files saved in OneDrive remain completely safe and untouched.

What should I do if the sign-in window keeps looping without asking for a password?

A looping sign-in window on macOS often indicates a network glitch blocking the authentication server, or corrupted app data. Try switching to a different network (like a mobile hotspot) or completely reinstalling the Microsoft 365 suite.

Login & Account Issues