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on January 15, 2026
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This tool also helps users fix Outlook syncing issues by repairing OST or PST files and syncing the data smoothly. This article attempts to address the most common synchronization errors. Unfortunately, covering every scenario in one document isn't possible. The following section describes different types of synchronization errors that can occur during the export operation to Microsoft Entra ID by using the Microsoft Entra connector. You can view directory synchronization errors in the Microsoft 365 admin center. To view errors with PowerShell, see Identify objects with DirSyncProvisioningErrors.
Fix the InvalidHardMatch error
This section discusses potential causes and solutions to resolving the error DeletingCloudOnlyObjectNotAllowed (Error Type 114). Ensure that the userPrincipalName attribute has supported characters and the required format. The result of the preceding scenarios is an IdentityDataValidationFailed error. We advise customers to enable BlockCloudObjectTakeoverThroughHardMatchEnabled unless they need it to take over existent accounts in Microsoft Entra ID. Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support.
We have resources to help you identify potential issues and fix them. You can assign the administrative role to the existing user object again after the soft match between the on-premises user object and the Microsoft Entra user object has finished. Microsoft Entra Connect isn't allowed to soft match a user object from on-premises AD with a user object in Microsoft Entra ID that has an administrative role assigned modern authentication troubleshooting to it.
Fix the Existing Admin Role Conflict error
The Users Processed count will be 0 is there are no users in the synced dataset after filtering. A duplicate value click the next website page is assigned to an already synced object, which conflicts with another synced object. After these instructions, ensure the sync settings are correct and check everything is working well. The error message in the Summary sheet of the Sync Summary spreadsheet attachment can also highlight the reason for this.
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Knowing the reasons behind the Outlook sync Fix Outlook and Office365 Sync Issues issues will help us to fix this problem and prevent issues in communication and workflow. 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. Find out what to do if you are having issues with syncing users or groups from Microsoft 365. The Microsoft Entra Connect client is failing to delete users during migration from hybrid to cloud only, resulting in Error Type 114. Microsoft Entra ID enforces various restrictions on the data itself before allowing that data to be written into the directory. These restrictions are to ensure that end users get the best possible experience while using the applications that depend on this data.
What should I do if my sync failed due to authentication issues?
The system requires that users have a first name, last name and a valid email address that conforms with your domain lock if enabled. To get the sync working you will either need to delete users or have the user limit on your account increased. The most common reason for missing users is that you've run a Test Sync, instead of a Manual Sync.
We have resources to help you identify potential issues and fix them.You can stop any accounts from being brought over by adding them to the sync deny list.The system requires that users have a first name, last name and a valid email address that conforms with your domain lock if enabled.This software allows users to process numerous OST files at once without any size limitations.Examples include revoked or expired certificates and outdated or unnecessary addresses, such as SMTP, X.400, X.500, MSMail, and CcMail.The sync will fail if the total number of all users (active or inactive) on your account exceeds the user limit placed upon it if present.Once you have completed the steps to fix Outlook sync errors, kindly check if the error has been fixed or not.
If that doesn't resolve your missing users issue, please follow our guide to troubleshooting missing users below. After viewing, see fixing problems with directory synchronization for Microsoft 365 to correct any identified issues. To resolve these issues you should run the steps in this article and check whether the groups in your sync's filtering preference contain users in Azure AD. The sync will fail if the groups you selected to load users from no longer exist in Azure AD. Typically this is because the selected groups have been deleted from Azure AD since the M365 sync was configured on your account.
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.
Method 4: Recreating the Outlook Profile
You can stop any accounts from being brought over by adding them to the sync deny list. 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. You will need to have the correct privileges set on your Azure account in order to set up the M365 sync. This section discusses LargeObject or ExceededAllowedLength errors.