Sign-in & Login Problems

How to Fix Microsoft 365 Sign-In Error 1001 on Mac

Aamir Naveed Akram Sep 28, 2026 869 views

Question details

The user needs to resolve a sign-in failure when attempting to log into Microsoft 365 applications on a Mac.

How to Fix Microsoft 365 Sign-In Error 1001 on Mac

Product: Microsoft 365
Device & OS: macOS
Scenario: Signing into Microsoft 365 desktop applications to activate the software or access cloud services.
Observed behavior: The login process fails and displays the error message 'Something went wrong [1001]'.

Before you start

Before proceeding, ensure you have your Microsoft 365 account credentials handy and save any open work, as you will need to quit all Office applications and restart your Mac.

Solution 1Recommended

Clear Mac Keychain and Run the Office License Removal Tool

This solution resolves the error by clearing corrupted Office credentials and deleting outdated or conflicting license data from your Mac.

Error 1001 is typically caused by stale authentication tokens or corrupted license files on your macOS system. Clearing these allows Microsoft 365 to generate fresh credentials upon your next sign-in.

Quit all Office applications

Ensure that all Microsoft Office applications, including Word, Excel, PowerPoint, and Outlook, are completely closed on your Mac.

Open Keychain Access

Click on Finder, navigate to Applications > Utilities, and double-click on 'Keychain Access' to open it.

Remove Office identities

In Keychain Access, use the top-right search bar to look for 'Office'. Delete any identity entries or passwords related to Microsoft Office.

Run the license removal tool

Download the official Microsoft Office License Removal Tool from the Microsoft Support website. Open the downloaded file and follow the on-screen prompts to clear your license data.

Restart and sign in

Restart your Mac. Open any Microsoft 365 desktop application and sign in again with your account credentials to reactivate your software.

Clear Mac Keychain and Run the Office License Removal Tool

Missing Keychain Entries: If you do not see any Microsoft Office entries saved in Keychain Access, simply skip that step and proceed directly to running the license removal tool.

Free Microsoft Office alternative

Switch to WPS Office to Avoid Login Interruptions

If Microsoft 365 sign-in errors like 1001 continue to disrupt your workflow on Mac, consider switching to WPS Office. It provides a lightweight, highly compatible, and free alternative without the complex login or licensing issues.

1. Download WPS Office: Visit the official WPS website and download the macOS version of WPS Office.
2. Install the application: Open the downloaded installer and drag the WPS Office icon to your Applications folder.
3. Open your documents: Launch WPS Office and directly open your existing Microsoft Office files without worrying about complex activation errors.

Fully compatible with Microsoft Word, Excel, and PowerPoint formats (.docx, .xlsx, .pptx).Free to use with a familiar, easy-to-navigate user interface.Lightweight design that consumes fewer system resources on your Mac.No mandatory sign-ins required for basic offline document editing.

Frequently Asked Questions

What causes the Microsoft 365 Error 1001 on Mac?

Error 1001 is typically caused by corrupted Office credentials stored in your Mac's Keychain Access, conflicts with identity entries, or outdated Microsoft Office license data.

Does running the license removal tool delete my documents?

No, the license removal tool only removes the activation files and license data for Microsoft Office. It does not affect, delete, or alter any of your personal documents or files.

What if the license removal tool doesn't fix the 1001 error?

If clearing the Keychain and running the removal tool fails, ensure your macOS is fully updated. You may also need to completely uninstall Microsoft 365, empty the trash, and reinstall the latest version from the official portal.

Login & Account Issues