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After installing the September Public Update, Outlook 2007 displays mixed languages in the user interface. You can start Outlook in safe mode, disable your add-ins, and then try to open Outlook normally. If you can't open Outlook, or Outlook disappears or crashes, one of your add-ins may be to blame or you may need to update Outlook. If you are having problems with Outlook, there are a few things we can help with to get you back to sending and receiving your email.
Outlook known issues in the October 2019 updates
Please install the Windows 10 Fall Creators Update to fix this issue. Outlook 2016 freezes when you try to preview an Excel file that's attached to an email. After updating Office, you may experience a brief flashing window every hour, which triggers the OfficeBackgroundHandlerRegistration task to start running. Exchange connectivity diagnostic 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.
Outlook Known issues in December 2024 updates
The person who sent you the invitation will need to remove your permissions and then send a new invitation. 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.
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 credential loop in Microsoft 365 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 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.
- 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.
- 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.
- The folder may have been deleted or the server where the folder is stored may be unavailable.
- If the network is performing slowly, Outlook must wait for read and write operations to the AppData directory to finish.
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.
Can't open Enterprise Vault items

Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support. If you use the cloud-based Microsoft how to fix Outlook not opening today 365 on a PC or Mac, the automated Support and Recovery Assistant tool can diagnose and fix many issues, including Microsoft Outlook not starting. You may have to contact your antivirus software vendor to determine how to configure the software to exclude any integration with Outlook or to exclude scanning in Outlook. For a list of antivirus software vendors, see Consumer antivirus software providers for Windows. If the problem doesn't occur after you restart Outlook, one of the add-ins is likely the cause of the problem. Restore the add-ins one at a time until the problem does occur to determine which add-in is causing the problem.