If you can open the original Outlook Data File, you might be able to recover additional items. The Inbox Repair tool creates a backup file with the same name as the original, but with a .bak extension, and saves it in the same folder. There may be items in the backup file that you might be able to recover that the Inbox Repair tool couldn't.

If Outlook is set to only download headers, each time you access the email it has to connect to your server to retrieve the body of the email, which takes time. Downloading the Outlook Fix Blog full email will keep it local so later access is much faster. Delaying non-essential updates, in some cases, allows Microsoft to refine them further before they are installed. We recommend that you don’t have monthly updates enabled for Office 365 ProPlus, as these have been known to cause intermittent issues. The most practical version to use is the semi-annual release. There is a new version of Outlook available, which depending on company policy, can be user activated.

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 Outlook Fix Blog frozen.

One of the failed sign-in windows showed a long string under a field labeled Microsoft Information Protection API. Running that value through the Entra admin portal revealed what we needed. At that point, the focus shifted to what was happening during authentication. The answer came from a closer look at the Microsoft Entra sign-in logs and a hidden dependency that I wasn’t aware of.

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. We're investigating the issue and will update this page when a fix is available.

Out-of-date software and corrupted Outlook profiles are two of the most common issues that can prevent you from sending and receiving email. If you're an admin with multiple users reporting problems, you also should check for service issues with Microsoft 365. This kind of error usually indicates some issues on the disk where your Outlook PST file is located. It can be caused due to improper installation of a program, corruption in the hard drive or registry file, etc. This has nothing to do with the email client