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 credential loop in Microsoft 365 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 resolve Outlook not sending emails fast 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

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. Note that you can quickly tell how your mail is currently sorted, by the presence of a small triangle on the field headers.

• To keep up with new viruses as they're created, antivirus software vendors periodically provide updates that you can download from the Internet.
• If everything is working correctly, you can now delete the old profile.
• Here are some common fixes that should work when Outlook doesn't open, whether you're using Windows or a Mac.
• You might need to set Windows Update to automatically download and install recommended updates.
• When you install Outlook, an Inbox repair tool (scanpst.exe) is also installed on your PC.
• We're investigating the issues and will update this page when a fix is available.

Outlook Known issues in May 2024 updates

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.

Can't open Enterprise Vault items

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 reset cached Exchange mode during certain operations.