Incorrect Outlook settings can also be one of the reasons behind Outlook synchronization errors. The Support and Recovery Assistant, a tool provided by Microsoft, can identify and resolve common Outlook problems. It is capable of automatically Outlook OST vs PST repair 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. Outlook’s ability to connect to the mail server may be blocked by firewalls or antivirus software.

Turn off Windows Defender Security Center

If there's a feature you think is missing from the Mail and Outlook data file cannot be accessed Calendar apps, or if a feature in isn't working properly, you can provide feedback directly to the Mail and Calendar team. Two-factor authentication helps protect your account by making it more difficult for someone else to sign in. It verifies your identity using your password and a contact method (also known as security info). If you would like to ask me another question in the future or follow up on your current question, you can add me as a favorite Expert.

Check if two-factor authentication is turned on for your account

Once the client started using Outlook again after some time has passed the issue had come back. I ran the PSTscan tool to check for anomalies on the OST file (which it found and repaired but the issue still occurs). I’ve tried to set cache mode from 1 year all the way down to a few days.

Check Antivirus and Firewall Settings

• If you're using an Exchange account that requires advanced settings, you'll need to remove the account and add it again using advanced settings.
• After you’re satisfied, turn off your firewall or antivirus program for a while.
• Windows Defender Security Center is free security software that's included with Windows 10.
• In some cases setting up a new computer replacement was the only option to fix these odd Outlook Sync issues.
• Tempted to create a Test Shared Mailbox, but thinking that wouldn't be an accurate test for inbound mail, etc. or just actually tested by the Users at all.
• We have shared five manual methods in this blog to resolve the Outlook syncing errors.
• However, I cannot find any reason why his account would do this only on our domain nothing is blocking our connection to Office 365.

However, in some situations these processes can take up to 24 hours. We're in the process of migrating from On-Premise Exchange to O365. I Repair Outlook Profile Online 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.

Free Methods to Remove Duplicate Items in Outlook 2016

If you're using an Exchange account that requires advanced settings, you'll need to remove the account and add it again using advanced settings. To add the account using advanced settings, see Add an account using advanced setup. Knowing the reasons behind the Outlook sync issues will help us to fix this problem and prevent issues in communication and workflow. If you still can't sync your email after removing your account and adding it again, you might need to add the account using advanced setup. If I check the sync log I see a lot of sync errors for Inbox, sent items and a few other folders.