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. Maybe you've added a new program to your computer that doesn't get along with Outlook, or your system has a virus. Regardless of the specific cause, there are several key troubleshooting fixes to try that might help. If your antivirus software isn't up-to-date, Outlook may not function correctly. Outlook stores certain data, such as email signatures and the spelling checker dictionary, in the AppData folder.

Outlook known issues in the October 2019 updates

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. When you start Windows normally, several applications and services start automatically and then run in the background. A Selective Startup or "clean boot" process can help you identify problems that are caused by application conflicts. The issues documented in this section have been reported after installing the recent Outlook profile repair and recovery steps updates listed below. We're investigating the issues and will update this page when a fix is available. In the meantime, please use the workarounds suggested for each issue.

Outlook Known issues in December 2024 updates

This happens to accounts that are configured in the iOS Mail app. Until you can install the Windows Update fix release, you can set a registry key 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. 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. If you've already clicked the Accept button in Outlook 2016, you won't be able to re-accept the invitation from another Outlook application.

Outlook Known issues in April 2023 updates

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. 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. If you're using Outlook 2010, Outlook 2013 or Outlook 2016, uninstall and re-install work offline mode stuck iCloud to resolve this issue. This issue affects all Outlook versions on Windows 7, Windows 8, Windows 10.

VBScript does not run or you receive malicious code warning when using a custom form for Outlook

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. This occurs because custom form script is now disabled by default. You must have at least three user accounts on the computer to complete these steps. You can automatically repair your Office program files to resolve such problems as Outlook freezing or not responding. Outlook forwards meeting invitations to other attendees without anyone actually sending an update or forwarding an invite.

• To manage your mailbox by using the AutoArchive feature, see AutoArchive settings explained.
• To learn more about how to send us feedback, please see How do I give feedback on Microsoft Office.
• To use the Inbox repair tool, exit Outlook, and then follow the steps in Repair Outlook Data Files (.pst and .ost).
• There are three steps you can take to try to get Outlook working again.
• We're investigating the issue and will update this page when a fix is available.
• When you start Windows normally, several applications and services start automatically and then run in the background.
• To install the latest Windows and Office updates, click the link below.

Here are some common fixes that should work when Outlook doesn't open, whether you're using Windows or a Mac. To manage your mailbox by using the AutoArchive feature, see AutoArchive settings explained. We recommend that you move several items in your larger folders to separate folders, or that you archive those items by using the AutoArchive feature. These steps are provided in a specific order based on commonality and complexity. Find solutions to common problems or get help from a support agent.





User profiles help make sure that your personal preferences are used when you log on to Windows. As your mailbox size increases, more resources are required to open each folder. If you have a large number of items in any single folder, you may experience performance issues Fix Outlook and Office365 Sync Issues during certain operations.