Third-party add-ins are among the most common culprits for Outlook not opening properly. Safe Mode allows you to start Outlook with all extensions temporarily disabled. You don't have permission to create an entry in this folder. Right-click the folder, and then click Properties to check your permissions for the folder. See the folder owner or your administrator to change your permissions. Currently, you can't use Outlook on Windows to edit calendars that are shared with your Outlook.com account, even if you've reconnected your Outlook.com account to Outlook.

Disable Hardware Graphics Acceleration

If your Outlook suddenly stopped opening after a Windows update, don’t panic. Most startup failures arise from minor configuration mismatches or outdated components. Following the above steps—from safe mode diagnostics to repairing data files—will restore functionality in most cases.

Do you see the message "This set of folders could not be opened"?

• Once the scan completes, reopen Outlook and check if the issue is resolved.
• Outlook not opening on Windows 11 is usually caused by corrupted files or conflicting add-ins, but with the above methods, you can easily fix it.
• Occasionally, classic Outlook tries to run a process in the background.
• If so, wait a short time (usually two or three minutes) to see if Outlook starts working again.
• This process checks for structural issues and automatically fixes them.
• To access the calendar shared with your Microsoft 365 for business account, you'll need to accept the invitation from Outlook on the web, iOS, or Android.

In this guide, FixTechGuide explains the top causes and provides simple step-by-step solutions to help you fix Outlook not opening on Windows 11 quickly. Until you can install the Windows Update fix release, you can set a registry key Fix Outlook and Office365 Sync Issues that will cause Outlook to stop using the local Windows Search service. When this registry key is set, Outlook will use its own built-in search engine. The built-in search will display the message below to indicate it is not using the Windows Search service.

Outlook known issues in the Jan 2018 updates

The loading of unregistered MAPI services has been disabled by default to make Outlook more secure. To edit a shared calendar, go online to your own Outlook.com calendar, open Calendar for Windows 10, or use a mobile device. Read how to Add your Outlook.com account to another connection status shows disconnected mail app.

Outlook known issues in the November 2019 updates

Once the scan completes, reopen Outlook and check if the issue is resolved. Go to File → Options → Add-ins → disable all add-ins, then re-enable them one by one to find the faulty one.



If you've already clicked recreate Outlook profile step by step the Accept button in Outlook 2016, you won't be able to re-accept the invitation from another Outlook application. The person who sent you the invitation will need to remove your permissions and then send a new invitation. This command deletes the custom folder views, restoring default configurations. It’s harmless and resolves 30% of stuck startup issues according to Microsoft community reports.





This occurs because custom form script is now disabled by default. Are you struggling to open Microsoft Outlook on your Windows 11 PC? Many users face this frustrating issue after a Windows update or due to corrupted Outlook data files.





By the end, you’ll know exactly how to restore your Outlook and prevent future errors. If your Microsoft Outlook won’t open after a recent Windows update, you’re not alone. Many users encounter startup freezes, profile loading loops, and crashes following major Windows patches or Office updates.

FixTechGuide’s free email diagnostic tools automate error detection by scanning your configuration files, registry entries, and mail protocols. The platform validates SMTP, IMAP, and POP3 settings against verified databases to identify version mismatches or broken profiles introduced after system updates. You can also add the secondary connected accounts (Gmail, Yahoo, etc.) in Outlook.com as additional accounts in the Outlook profile. To access the calendar shared with your Microsoft 365 for business account, you'll need to accept the invitation from Outlook on the web, iOS, or Android.