We can help you find a solution or connect you to technical support. This restores missing or corrupted Office components that affect search indexing. If a Microsoft 365 application such as Word or Excel isn't working correctly, sometimes restarting it will fix the problem. Download the tool from Microsoft and run the Outlook diagnostic to auto-detect server and account issues.

⃣ Reset Browser Cookies & Cache

If your admin enabled Modern Authentication (MFA), try disabling it temporarily via Azure Active Directory → Properties. Alternatively, generate an app-specific password if using Outlook 2016 or older. This resets your authentication cache and forces a fresh token request.

Microsoft 365 Apps Crashing After Update — Step-by-Step Repair Guide

• The steps to access the repair tool vary depending on your operating system.
• It automatically diagnoses and repairs many Office 365 problems — including search indexing and sync issues.
• This guarantees clean configuration files and resolves deep-level corruption issues.
• The Microsoft 365 Copilot app brings together your favorite FixTechGuide Office 365 support apps and Copilot in one intuitive platform.
• If your admin enabled Modern Authentication (MFA), try disabling it temporarily via Azure Active Directory → Properties.
• We provide instant guidance for update errors, installation failures, and Office activation issues.
• This service description uses the generic title administrator to refer to all categories of administrators.
• Microsoft 365 crashes after updates can be frustrating, but these fixes will restore stability quickly.
• For more self-help resources, see Microsoft 365 operated by 21Vianet.

For iPhone users, reinstalling Outlook or updating to the latest iOS often resolves stuck sign-in loops instantly. Many users have both personal Microsoft accounts (e.g., FixTechGuide Office 365 troubleshooting Outlook.com) and work/school Office 365 accounts. If both are signed in simultaneously, the system can confuse the authentication path.

? Fix Office 365 Login Issues on Mobile

If all else fails, uninstall Microsoft 365 completely, remove remaining registry traces using the Office Uninstall Support Tool, and reinstall it fresh. This guarantees clean configuration files and resolves deep-level guide to Office 365 sign-in errors corruption issues. Partial updates often break compatibility between Windows libraries and Office binaries.

Step 2 – Update Outlook and Office 365

Go to Settings → Windows Update and install all pending updates. Then open any Office app → File → Account → Update Options → Update Now to ensure both are synchronized. Go modern authentication troubleshooting to Control Panel → Programs and Features, select Microsoft 365, and click Change → Quick Repair.

Repair Outlook OST File Not Working in Office 365 – Complete Fix (

Microsoft 365 with Microsoft Teams helps deliver a complete, secure solution to help everyone work better, smarter, and more cohesively. Microsoft Create has professionally designed, fully customizable templates to help you get things done. Find solutions to common problems or get help from a support agent.