The diagnostic will guide disable faulty add-ins in Outlook you to resolve various error conditions that can cause mailboxes to not be created. The most common cause of an out-of-date account is an incorrect password. In the notification bar at the top of the app, select Fix account.

Turn off Windows Defender Security Center

It also provides the option to export the Outlook OST file into Office 365 and Live Exchange mailboxes. This software also has a splitter option to split large-sized PST files into smaller ones, helping users prevent oversized PST file issues. Outlook sync issues can be because of corrupted Outlook OST or PST files. Therefore, now we will know the steps to repair the Outlook data file. We’ve Fix Outlook and Office 365 Errors 2025 had sync issues with employees from time to time however, re doing the mail profile or wiping the Windows profile usually fixes it. In some cases setting up a new computer replacement was the only option to fix these odd Outlook Sync issues.

Check if two-factor authentication is turned on for your account

Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support. These are the only two I've seen have this issue and I was wondering if you've seen this and figured out a 'fix'? Tempted to create a Test Shared Mailbox, but thinking that wouldn't be an accurate test for inbound mail, etc. or just actually tested by the Users at all.

Check Antivirus and Firewall Settings

• Before we know the solutions, we will understand a few common causes of the Outlook sync problem.
• Outlook’s ability to connect to the mail server may be blocked by firewalls or antivirus software.
• There are various methods to resolve the Outlook sync issues, including manual and third-party solutions.
• Now, we will verify the server settings to fix the Outlook synchronization error.
• I’ve unchecked download shared folders when setting up a new Outlook profile.

You'll have the option to do that on your "My Questions" page by clicking the heart icon labeled My Favorite. Please reply with your results when you have completed the steps above. Additionally, you might want to make a new profile and make it the default to see if it fixes the problem. However, his OST file is not anywhere near that size it’s about 5GB. I was wondering if anyone had some insight into an issue I am having with credential loop in Microsoft 365 a client. The service typically takes less than 30 minutes to provision a user or to sync changes for a user.

Free Methods to Remove Duplicate Items in Outlook 2016

The Mail and Calendar apps for Windows 10 don't support two-factor authentication. If two-factor authentication is turned on for your account, you'll need to create an app password for that account. An app password is used instead of your normal account password for apps that don't support two-factor authentication. Before you begin, make sure that your device has the latest operating system and app updates. Try the general troubleshooting solutions in Troubleshooting Mail and Calendar apps for Windows 10. I regret that you are experiencing issues with your Microsoft Outlook slow synchronizing inbox message, and need help speeding up.