If you have a large number of items in any single folder, you may experience performance issues during certain operations. For more information, see Outlook performance issues when there are too many items or folders in a cached mode .ost work offline Mode stuck or .pst file. To create a user profile, you must first create a user account. To determine whether this problem is caused by a corrupted user profile, create a user profile to see whether the problem still occurs when you use the new profile. To keep up with new viruses as they're created, antivirus software vendors periodically provide updates that you can download from the Internet.

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

You can also add the secondary connected accounts (Gmail, rebuild Outlook data file quickly Yahoo, etc.) in Outlook.com as additional accounts in the Outlook profile. Your user profile is a collection of settings that let you customize the computer appearance and performance. It contains settings for desktop backgrounds, screen savers, sound settings, and other features. 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.

Outlook Known issues in September 2024 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.
• Note that you can quickly tell how your mail is currently sorted, by the presence of a small triangle on the field headers.
• You can automatically repair your Office program files to resolve such problems as Outlook freezing or not responding.
• Occasionally, classic Outlook tries to run a process in the background.
• 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.
• 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.

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.

Outlook known issues in the June 2018 updates

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. 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.

Outlook Known issues in November 2023 updates

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 iCloud to resolve this issue. This issue affects all Outlook versions on Windows 7, Windows 8, Windows 10. After installing the September Public Update, Outlook 2007 displays mixed languages in the user interface.



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. If the network is performing slowly, Outlook must wait for read and write operations to the AppData directory to finish. To manage your mailbox by reducing the size of the Outlook data file, see Reduce the size of Outlook Data Files (.pst and .ost). Although add-ins can enhance your user experience, they can occasionally interfere or conflict with Outlook. There is currently no option to revert to the prior behavior, but we would love to hear your feedback to modern authentication troubleshooting help us with future designs.

Step 2 - Make sure that Outlook isn't in use by another process

Occasionally, classic Outlook tries to run a process in the background. Auto-archive, sending and receiving a very large attachment, or running some of the other mailbox tools can all be done in the background. Check the status bar at the bottom of the screen to see if another process is running. If so, wait a short time (usually two or three minutes) to see if Outlook starts working again. If you can't choose any of the menu options, type inside an email message, calendar event, or contact, Outlook may have frozen. There are three steps you can take to try to get Outlook working again.

Outlook Known Issues in November 2021 updates

Outlook forwards meeting invitations to other attendees without anyone actually sending an update or forwarding an invite. 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.