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 Repair Outlook Profile Online 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

Many of these items can be automatically checked by the Classic Outlook Advanced Diagnostics troubleshooter. 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. Another options is to use the Filter Email button on the ribbon.

Outlook Known issues in April 2023 updates

When you install Outlook, an Inbox repair tool (scanpst.exe) is also installed on your PC. The Inbox repair tool can resolve problems by scanning your Outlook data files, and repair PST file without data loss repairing errors. To use the Inbox repair tool, exit Outlook, and then follow the steps in Repair Outlook Data Files (.pst and .ost). If your antivirus software includes integration with Outlook, you may experience performance issues. You can disable all Outlook integration within the antivirus software.

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.

• 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 the check box is cleared, the service or startup program doesn't run when you restart the computer.
• 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.
• After updating Office, you may experience a brief flashing window every hour, which triggers the OfficeBackgroundHandlerRegistration task to start running.
• Outlook 2016 freezes when you try to preview an Excel file that's attached to an email.
• Download the latest updates by visiting your antivirus software vendor's website.
• If the network is performing slowly, Outlook must wait for read and write operations to the AppData directory to finish.
• To edit a shared calendar, go online to your own Outlook.com calendar, open Calendar for Windows 10, or use a mobile device.

Outlook Known issues in May 2024 updates

Or, you can disable any antivirus software add-ins that are installed in Outlook. If you have email messages in an email program, you must import your email messages and addresses to the new user profile before you delete the old profile. If everything is working correctly, you can now delete the old profile. In System Configuration, if you select a check box, the related service or startup program runs when you restart the computer.





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 FixTechGuide support for Office 365 during certain operations.