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 rebuild Outlook data file quickly send they get an error that the message has been deleted. Ive repaired the OST and changed cache mode to only cache 1 year.

• These are the only two I've seen have this issue and I was wondering if you've seen this and figured out a 'fix'?
• To view errors with PowerShell, see Identify objects with DirSyncProvisioningErrors.
• If you are still facing this issue, kindly follow the solutions below to fix the sync issues in Outlook.
• Always make sure your profile and settings are set up correctly, your software is up to date, and your connection is steady.
• This software also has a splitter option to split large-sized PST files into smaller ones, helping users prevent oversized PST file issues.
• Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support.
• You can view your inactive users on the Users page and delete them as you see fit.

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 Outlook OST vs PST repair 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 Microsoft Outlook Email Repair Tool Online 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.





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.