Bug fixes, new features, and performance enhancements are released regularly. If you try to delete or move a large number of messages at once, Outlook can appear to freeze, but really, it's working behind the scenes. Check the status bar at the bottom of the screen. If Outlook is performing some operation on hundreds or thousands of messages at once, it might appear to be stuck. Give Outlook a few minutes to finish the process and it should start to work again. 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.

If so, wait a short time (usually two or three minutes) to see if Outlook starts working again. A profile is a group of settings that controls how Outlook works. It includes a listing of your accounts, autocomplete information, and your name and initials. To repair your Outlook profile or create a new one, see Fix your Outlook email connection by repairing your profile. If that message has an attachment that's larger than 20MB, delete the attachment and either attach a smaller file or attach a link to the attachment. For more information, go to Reduce attachment size to send large files with Outlook or Exchange Online limits.

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. We're working to make it possible to edit shared calendars in Outlook 2016 for Windows. 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. You can use Fix Outlook Site Microsoft Support and Recovery Assistant to diagnose both Calendar and Mail issues that affect Outlook. To download and install the Assistant, see About Microsoft Support and Recovery Assistant. In some cases, an Outlook messaging profile may be misconfigured.

If your antivirus software includes integration with Outlook, you may experience performance issues. You can disable all Outlook integration within the antivirus software. Or, you can disable any antivirus software add-ins that are installed in Outlook.

If Outlook works in Outlook Safe Mode but resetting your dat-files did not help, then the issue is most likely caused by an add-in. When typing, please note the space between outlook.exe and /resetnavpane.If you encounter this issue more often, see this Quick Tip to find a more definitive solution. If Outlook shows an error like "Cannot open attachments", this could be due to unsupported Fix Outlook Site file formats, outdated Outlook versions, corrupted attachments, or security restrictions. Please install the latest updates on your phone to resolve the issue. 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.

Bookmark this page so that whenever you come across an error like your Outlook calendar not syncing, or a corrupted file, you'll have a place to start troubleshooting. 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. Availability has recovered, and engineers are investigating the root cause and identifying problematic servers. The team is sweeping all remaining capacity to identify and address residual issues. You can use the Inbox Repair tool (SCANPST.EXE) to diagnose and repair errors in your Outlook data file. The Inbox Repair tool checks the Outlook data files on Fix Outlook Site your computer to see if they're in good shape.

While we fix the problem, you can send the file as a OneDrive link. When users select the Manage Microsoft Storage quota link at the bottom corner in Outlook.com, they are taken to a blank Settings page. 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. You can check the location of your Outlook Data Files in Outlook. Gmail has a positive reputation when it comes to spam filtering.

Having too many shared mailboxes and Fix Outlook Site folders can cause slow performance in Outlook. The limit will depend on the size of the mailboxes and folders. It is recommended to remove any mailboxes that don’t need to be open. You can also add the secondary connected accounts (Gmail, Yahoo, etc.) in Outlook.com as additional accounts in the Outlook profile.

For more information on creating a new email profile, see Create an Outlook profile. To start Outlook in safe mode, press the Windows key on your keyboard. In the search box, type outlook.exe /safe, then press Enter. Repairing is a simple process but may take as long as half an hour to complete.

Our relationship to the Microsoft Partner Network allows us to provide competitive pricing and authentic software and support, all with a much-needed human element. The "Cannot open the Outlook window" error can be fixed quite easily. 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. There is currently no option to revert to the prior behavior, but we would love to hear your feedback to help us with future designs. To learn more about how to send us feedback, please see How do I give feedback on Microsoft Office.