After updating Office, you may experience a brief flashing window every hour, which triggers the OfficeBackgroundHandlerRegistration task to start running. For more information about when builds are available for their respective channels, go to Update history for Microsoft 365. We're investigating the issue and will update this page when a fix is available. MAPI does not validate that a provider's DLL that it is requested to load is registered correctly in MapiSVC.inf or even that it comes from the local machine. This can be exploited by creating a file together with an OLE object in such a way to cause MAPI to load a DLL from a network share when the OLE object is activated.

My Outlook 365 won't open after a Windows update yesterday.

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. Note that you can quickly tell how your mail is currently sorted, by the presence of a small triangle on the field headers. Outlook 2016 freezes when you try to preview an Excel file that's attached to an email. This issue affects all Outlook versions on Windows 7, Windows 8, Windows 10.

Outlook Known issues in June 2022 updates

The only other change to the Exchange Server was a certificate update for IIS. This is a standard DigiCert wildcard cert that we have replaced every year with no issues. If you 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. 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.

Outlook Known Issues in June 2021 updates

The loading of unregistered MAPI services has been disabled by default to make Outlook more secure. 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. We're working to make it possible to edit shared calendars in Outlook 2016 for Windows. We've run into some issues with the 'New' Outlook this week after 6+ months of usage that other may run into.

Some Web-based Outlook add-ins don't work in when using on premise Exchange 2013

• See the folder owner or your administrator to change your permissions.
• After updating Office, you may experience a brief flashing window every hour, which triggers the OfficeBackgroundHandlerRegistration task to start running.
• This command deletes the custom folder views, restoring default configurations.
• If you typically use an Outlook.com account for email, this issue can occur if there are multiple aliases on the account and the 3rd party email address is the primary alias.
• To edit a shared calendar, go online to your own Outlook.com calendar, open Calendar for Windows 10, or use a mobile device.
• I am opening the "classic" Outlook app on my computer because the one labeled new seems to not actually be a functioning app (no icon, nothing happens when I click on it).

My computer (running Windows 11 Pro) forced an update about two weeks ago. Since the update, my Outlook will not return to "new" Outlook, it deleted my email signature, and is incredibly delayed in getting messages. I am opening the "classic" Outlook app on my computer because the one labeled new seems to not actually be a functioning app (no icon, nothing happens when I click on it). When the Outlook app opens, I can see the 'Try FixTechGuide mailbox repair steps the new Outlook' toggle. The toggle just turns back off and the app does nothing different.



This occurs because custom form script is now disabled by default. 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. Online Repair reinstalls Outlook modern authentication troubleshooting components while preserving your data, resolving DLL and registry mismatches that prevent startup. This process checks for structural issues and automatically fixes them.

Getting Started Is Easy

To edit a shared calendar, go online to your own Outlook.com calendar, open Calendar for Windows 10, or use a mobile device. Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support. You can start Outlook in safe mode, disable your add-ins, and then try to open Outlook normally. To access the filtering options faster, add them to your Quick Access Toolbar. 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.

Repair Outlook OST File Not Working in Office 365 – Complete Fix (

This ensures Outlook and Windows run the same DLL versions and registry references. Third-party add-ins are among the most common culprits for troubleshoot Outlook synchronizing folders error Outlook not opening properly. Safe Mode allows you to start Outlook with all extensions temporarily disabled.