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 Most startup failures arise from minor configuration mismatches or outdated components.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.
• 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.
• 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.
• Right-click the folder, and then click Properties to check your permissions for the folder.
• 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 FixTechGuide Windows update Outlook fix 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

This issue affects all Outlook versions on Windows 7, Windows 8, Windows 10. If you Troubleshoot Office 365 Sync and Login Issues can't open Outlook, or Outlook disappears or crashes, one of your add-ins may be to blame or you may need to update Outlook. If you are having problems with Outlook, there are a few things we can help with to get you back to sending and receiving your email. Sometimes, aggressive antivirus programs block Outlook’s execution. If Outlook opens, whitelist the Outlook process in your antivirus settings. This ensures Outlook and Windows run the same DLL versions and registry references.

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 Fix Outlook and Office 365 Errors 2025 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.





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.