This ensures Outlook and Windows run the same DLL versions and registry references.

Use Microsoft Support and Recovery Assistant (SaRA)

Go to File → Office solve Office 365 mailbox sync delays Account → Update Options → Update Now. The built-in Auto-Detect Utility ensures complete privacy—your credentials never leave your device. Run a full scan through the dashboard and receive a detailed report on configuration health, certificate status, and network connectivity.

Step 8 – Recreate Your Outlook Profile

• If it does, whitelist outlook.exe in your antivirus settings.
• Online Repair reinstalls Outlook components while preserving your data, resolving DLL and registry mismatches that prevent startup.
• There are three steps you can take to try to get Outlook working again.
• If Outlook opens, whitelist the Outlook process in your antivirus settings.
• Delete the existing group and click "New." Name it All Accounts and ensure both "Include this group in send/receive" options are checked.
• This forces Outlook to refresh all accounts automatically without requiring a restart.
• This command deletes the custom folder views, restoring default configurations.

Once back online, Outlook will immediately start syncing your mailbox with the server. It’s better to clear cache, recreate send/receive groups, and reset your profile for faster results. You can start Outlook in safe mode, disable your add-ins, and then try to open Outlook normally.

Why Outlook Fails to Update Until Restart

This solution prevents display rendering errors that occur after driver or DirectX updates. Third-party add-ins are among the most common Fix Outlook and Office 365 Errors 2025 culprits for Outlook not opening properly. Safe Mode allows you to start Outlook with all extensions temporarily disabled. Once the scan completes, reopen Outlook and check if the issue is resolved.

How to Fix Outlook Not Opening on Windows 11

Rebuilding OST and resetting send/receive fixes it in most cases. You might need to set Windows Update to automatically download and install recommended updates. Installing any important, recommended, and optional updates can often correct problems by replacing out-of-date files and fixing vulnerabilities. To install the latest Windows and Office updates, click the link below.



Delete the existing group and click "New." Name it All Accounts and ensure both "Include this group in send/receive" options are checked. This forces Outlook to refresh all accounts automatically without requiring a restart. Sometimes, aggressive antivirus programs block Outlook’s execution. If Outlook opens, whitelist reset Cached Exchange Mode the Outlook process in your antivirus settings.