If the connection is poor, consider restarting your modem/router or moving to a more reliable network. You will need to have the correct privileges set on your Azure account in order to set up the M365 sync. We're in the process of migrating from On-Premise Exchange to O365. I have a couple of Users and a Shared Mailbox that were migrated and both Users are experiencing issues with the Shared Mailbox updating on a regular basis. Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support. Additionally, you might want to make a new profile and make it the default to see if it fixes the problem.

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 inbox repair tool alternative send they get an error that the message has been deleted. Ive repaired the OST and changed cache mode to only cache 1 year.

• Sync failure alerts do not always include a full summary or attachment, you can run a test sync to obtain this data.
• If the connection is poor, consider restarting your modem/router or moving to a more reliable network.
• Outlook’s ability to connect to the mail server may be blocked by firewalls or antivirus software.
• The M365 sync establishes a synced dataset based on your M365 data and the filtering configuration of your sync.
• Both of our authentication methods can fail if the Enterprise Applications entry for the sync in Azure AD is deleted or if it has had its permissions modified.

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 online Outlook email repair utility recycle bin of users who you can delete when you no longer need them.





You can view your inactive users on the Users page and delete them as you see fit. Similarly you should review Fix Outlook and Office365 Sync Issues 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?

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.