Sometimes, Outlook sync issues can arise because of poor internet connection. If you are still facing this issue, kindly follow the solutions below to fix the sync issues in diagnose office activation conflicts 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.

Turn off Windows Defender Security Center

If the size of your .ost file is close to the limit, you could try increasing the limit on your client, restart Outlook and see if there is any difference. flush DNS and re-sync Outlook I’ve unchecked download shared folders when setting up a new Outlook profile. After performing these steps, Outlook’s all folders will be synced to the server. If this method doesn’t work for you, navigate to other solutions. Select the button below to launch a diagnostic in the Microsoft 365 admin center.

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

Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support. 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'? 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.

Check Antivirus and Firewall Settings

• I ran the PSTscan tool to check for anomalies on the OST file (which it found and repaired but the issue still occurs).
• It is capable of automatically identifying problems with account setups, sync, and other typical mistakes.
• Outlook sync issues can be because of corrupted Outlook OST or PST files.
• This software allows users to process numerous OST files at once without any size limitations.
• Knowing the reasons behind the Outlook sync issues will help us to fix this problem and prevent issues in communication and workflow.
• If two-factor authentication is turned on for your account, you'll need to create an app password for that account.
• Third-party firewalls or antivirus software might prevent you from syncing your email and calendar events.

If you can sync your email when the firewall is turned off, you'll need to allow the Office 365 sync problems and login fixes Mail and Calendar apps through the firewall. Windows Defender Security Center is free security software that's included with Windows 10. If you haven't installed alternative security software, you should temporarily turn off Windows Defender Security Center.

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.