
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 flush DNS and re-sync Outlook send they get an error that the message has been deleted. Ive repaired the OST and changed cache mode to only cache 1 year.
- Before we know the solutions, we will understand a few common causes of the Outlook sync problem.
- This blog talks about the causes behind Outlook synchronization errors and a few solutions to fix Outlook sync issues.
- This can happen for the a number reasons particularly if your sync authenticates using Delegated Permissions.
- Find out what to do if you are having issues with syncing users or groups from Microsoft 365.
- Typically this is because the selected groups have been deleted from Azure AD since the M365 sync was configured on your account.
Use the Microsoft Support and Recovery Assistant
If you are still facing this issue, kindly follow the solutions below to fix the sync issues in Outlook. If users are facing syncing issues in Outlook due to corrupt Outlook data files, they must choose a professional tool, like Shoviv OST to PST Converter Tool. This software allows users to process numerous OST files at once without any size limitations. Moreover, it maintains the folder hierarchy and metaproperties of the data when processing Outlook data files.
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. fix outlook and office 365 errors 2025 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 flush DNS and re-sync Outlook 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.
Fix Sync Issues and Local Failures in Microsoft Outlook: Problem Resolved!
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.