You can close the wizard at this point as you do not need to complete it for re-authentication to take effect. You should run a test sync after re-authenticating the sync to ensure it is working. Now, we will verify the server settings to fix the Outlook synchronization error. The sync will fail if the groups you selected to load users from no longer exist in Azure AD.

Common Causes of Sync Issues in Outlook

Knowing the reasons behind the Outlook sync issues will help us to fix this problem and prevent issues in communication and workflow. There can be several reasons for the Outlook synchronization error. Before we know the solutions, we will understand a few common causes of the Outlook sync problem. Find out what to do if you are having issues with syncing users or groups from Microsoft 365. It is possible for a corrupted Outlook profile to impede synchronization.

Fixing problems with directory synchronization for Microsoft 365

Sync failure alerts do not always include a full summary or attachment, you can run a test sync to obtain this data. The other solution to fix Outlook sync issues is recreating Microsoft Outlook profile. Incorrect Outlook settings can also diagnose Office activation conflicts be one of the reasons behind Outlook synchronization errors. So, follow the below steps to reset Microsoft Outlook settings. The M365 sync establishes a synced dataset based on your M365 data and the filtering configuration of your sync.

• To get the sync working you will either need to delete users or have the user limit on your account increased.
• The error message in the Summary sheet of the Sync Summary spreadsheet attachment can also highlight the reason for this.
• But setup is a little complicated and it can sometimes be difficult to identify the source of problems.
• Incorrect Outlook settings can also be one of the reasons behind Outlook synchronization errors.
• The sync will fail if the groups you selected to load users from no longer exist in Azure AD.
• If it does, you might need to include Outlook exceptions in the settings of your security program.

Use the Microsoft Support and Recovery Assistant

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. The most common reason for missing users is that you've run a Test Sync, instead of a Manual Sync. If that doesn't resolve your missing users issue, please follow our guide to troubleshooting missing users below. With directory synchronization, you can continue to manage users and groups on-premises and synchronize additions, deletions, and changes to the cloud.

How to Fix Outlook Sync Issues in Windows?

The sync will fail if it can't find any users that comply with your filtering preferences or the system's requirements for user records. The system requires that users have a first name, last name and a valid email address that conforms with your domain lock if enabled. The sync does not delete users but rather sets them to inactive. The idea is to provide a Fix Outlook and Office365 Sync Issues recycle bin of users who you can delete when you no longer need them.

Mailing Address

You can view your inactive users on the Users page and delete them as you see fit. Similarly you should review rebuild Outlook data file quickly the Users Deactivated sheet on the sync summary spreadsheet attachment as you can also delete these users to bring your total down. I have multiple users experiencing sync errors with Outlook and office365.





After these instructions, ensure the sync settings are correct and check everything is working well. To make sure there are no issues, click Test Account Settings to test the connection. Test other programs or websites to be sure Outlook is the only problem.



This tool also helps users fix Outlook syncing issues by repairing OST or PST files and syncing the data smoothly. There are various methods to resolve the Outlook sync issues, including manual and third-party solutions. Firstly, we will discuss a few manual methods to resolve this Outlook error and share the stepwise procedure of each method to successfully fix synchronization issues. Now, let us start with the manual processes to fix Outlook syncing errors.