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

Typically this is because the selected groups have been deleted from Azure AD since the M365 sync was configured on your account. Outlook’s ability to connect to the mail server may be blocked by firewalls or antivirus software. After you’re satisfied, turn off your firewall or antivirus program for a while. If it does, you might need to include Outlook exceptions in the settings of your security program. After viewing, see fixing problems with directory synchronization for Microsoft 365 to correct any identified issues. After performing these steps, Outlook’s all folders will be synced to the server.

Fixing problems with directory synchronization for Microsoft 365

Another which is shown below, is a user opens a new message, or replies to one, and lets it sit for a while. When they go back to the message and press diagnose Office activation conflicts send they get an error that the message has been deleted. Ive repaired the OST and changed cache mode to only cache 1 year.

• 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.
• You run the Microsoft consent process using an eligible M365 account after which you will be taken to the sync's setup wizard.
• Incorrect Outlook settings can also be one of the reasons behind Outlook synchronization errors.
• I have multiple users experiencing sync errors with Outlook and office365.
• 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.
• You will need to have the correct privileges set on your Azure account in order to set up the M365 sync.

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 Support and Recovery Assistant, a tool provided by Microsoft, can identify and resolve common Outlook problems. credential loop in Microsoft 365 It is capable of automatically identifying problems with account setups, sync, and other typical mistakes. To solve your Outlook issues, download the application from the Microsoft website and follow the directions.





You can view your inactive users on the Users page and delete them as you see fit. Similarly you should review resolve Outlook not sending emails fast 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.

What should I do if my sync fails because it can't find any users?

The error message in the Summary sheet of the Sync Summary spreadsheet attachment can also highlight the reason for this. This means that the authentication setup for your sync is no longer valid. This can happen for the a number reasons particularly if your sync authenticates using Delegated Permissions.



This blog talks about the causes behind Outlook synchronization errors and a few solutions to fix Outlook sync issues. We have shared five manual methods in this blog to resolve the Outlook syncing errors. Apart from this, we also discuss the Shoviv OST to PST Converter Tool, a professional way to repair, recover, and convert Outlook data files. This solution will be beneficial for users who are facing Outlook syncing issues because of corrupted PST or OST files. Users can also try its free demo version in their system and process the first 50 items from each folder freely. Always make sure your profile and settings are set up correctly, your software is up to date, and your connection is steady.