Upgrade to Microsoft solve Office 365 mailbox sync delays 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. The folder may have been deleted or the server where the folder is stored may be unavailable. To access the filtering options faster, add them to your Quick Access Toolbar.

• By the end, you’ll know exactly how to restore your Outlook and prevent future errors.
• To learn more about how to send us feedback, please see How do I give feedback on Microsoft Office.
• This solution prevents display rendering errors that occur after driver or DirectX updates.
• Third-party add-ins are among the most common culprits for Outlook not opening properly.
• If you're using Outlook 2010, Outlook 2013 or Outlook 2016, uninstall and re-install iCloud to resolve this issue.
• For more information about when builds are available for their respective channels, go to Update history for Microsoft 365.
• 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.
• We're investigating the issues and will update this page when a fix is available.

Outlook Known issues in October 2020 updates

After installing the September Public Update, Outlook 2007 displays mixed languages in the user interface. If you are having problems with Outlook, guide to Office 365 sign-in errors there are a few things we can help with to get you back to sending and receiving your email. Find solutions to common problems or get help from a support agent. Please install the Windows 10 Fall Creators Update to fix this issue.

Outlook known issues in the January 2019 updates

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 Outlook profile repair and recovery steps 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. If you're using Outlook 2010, Outlook 2013 or Outlook 2016, uninstall and re-install iCloud to resolve this issue.

Troubleshoot Outlook for Windows issues

Please install the latest updates on your phone to resolve the issue. 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.

Outlook Known issues in March 2025 updates

Stay updated, back up regularly, and enjoy uninterrupted productivity in your Outlook workspace. Online Repair reinstalls Outlook components while preserving your data, resolving DLL and registry mismatches that prevent startup. This process checks for structural issues and automatically fixes them. Occasionally, classic Outlook tries to run a process in the background.



When the Outlook app opens, I can see the 'Try the new Outlook' toggle. The toggle just turns back off and the app does nothing different. I saw a reply to an issue similar to mine that mentioned going to the Registry Editor and followed instructions outlined in that message but nothing changed. If your Microsoft Outlook won’t open after a recent Windows update, you’re not alone.