In the meantime, please use the workarounds suggested for each issue. For persistent issues, use FixTechGuide’s automated tools to perform deep diagnostics and security checks. Stay updated, back up regularly, and enjoy uninterrupted productivity in your Outlook workspace. This process checks for structural issues and automatically fixes them. After the repair, reopen Outlook to confirm successful startup.

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 Most startup failures arise from minor configuration mismatches or outdated components.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.
• 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.

There is currently no option to revert to the prior behavior, but we would love to hear your feedback to help us with future designs. To learn more about how to send us feedback, please see How do I give feedback on Microsoft Office. To access the filtering options faster, add them to your send/receive error 0x800CCC0E fix Quick Access Toolbar.

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 repair corrupted OST in Outlook 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 manually type in the secondary connected account email address in the "From" field, the email is sent as "On behalf of" your primary Outlook.com account. Please install the latest updates on your phone to resolve the issue. Outlook forwards meeting invitations to other attendees without anyone actually sending an update or forwarding an invite. This happens to accounts that are configured in the troubleshoot Outlook synchronizing folders error iOS Mail app. The issues documented in this section have been reported after installing the recent updates listed below. We're investigating the issues and will update this page when a fix is available.

Windows Command prompt running OfficeBackgroundHandlerRegistration task flashes every hour

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.





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. This often resolves startup errors caused by configuration issues.

Note that you can quickly tell how your mail is currently sorted, by the presence of a small triangle on the field headers. Another options is to use the Filter Email button on the ribbon. You may notice that All, Unread , Mentioned and other sort and filtering options, such as By date, and Newest are missing in Outlook above your email list.