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 Most startup failures arise from minor configuration mismatches or outdated components.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.
• Please install the Windows 10 Fall Creators Update to fix this issue.
• This process checks for structural issues and automatically fixes them.

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 how to fix Outlook not opening today 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 disable faulty add-ins 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've already clicked Repair Outlook Profile Online 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.





We're working to make it possible to edit shared calendars in Outlook 2016 for Windows. After installing the September Public Update, Outlook 2007 displays mixed languages in the user interface. Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support. The folder may have been deleted or the server where the folder is stored may be unavailable. You don't have appropriate permission to perform this operation.





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.