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. If you have a Google, Yahoo! Mail, iCloud, IMAP, or POP3 account, check the settings in the advanced mailbox settings to make sure they're configured to your email provider's specification. If you're using an Outlook.com, Microsoft 365, or Exchange account, you won't have advanced mailbox settings unless the account was set up using advanced setup. If your problem is how quickly mail populates, change the download preference to headers then full items.

This device doesn't meet the security requirements set by your email administrator

From there, make sure that the proper calendars are selected. If none of these steps address the syncing problem, escalate the issue to the IT team. Third-party firewalls or antivirus software might prevent you from syncing your email and calendar events.

Remove your account and add it again using advanced setup

In some cases, there might be outages or network-related issues, such as problems with a VPN. Mail flow issues can also arise out of other circumstances, such as a user having a mailbox in both Exchange Online and Exchange on-premises. In some cases, an issue might be related to MDM settings, such as restrictions on Outlook functionality, or user account and mailbox settings in Exchange. Sometimes an error appears in the Mail and Calendar apps when the apps try to sync new email or Outlook not syncing emails calendar events. These syncing problems usually happen because of issues like a damaged Outlook profile, poor internet connection, or a corrupted OST file.

Additional resources

• If you haven't installed alternative security software, you should temporarily turn off Windows Defender Security Center.
• Create your account and connect with a world of communities.
• I think Online Archive may be a harder sell but we need to do it anyway.
• If restarting Outlook or fixing the profile doesn’t work, converting the OST file is often the next step.
• In some cases, an issue might be related to MDM settings, such as restrictions on Outlook functionality, or user account and mailbox settings in Exchange.
• If it's a client-side issue, the admin can usually instruct the user on what steps to take.

When using Microsoft Teams on an iPhone, slow performance and app crashes can bring mobile work to a halt. Many issues come down to internet bandwidth or low storage space. If there's a feature you think is missing from the Mail and Calendar apps, or if a feature in isn't working properly, you canprovide feedback directly to the Mail and Calendar team.

Troubleshooting issues with iPhone Outlook not syncing

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. We're sorry you're having problems with the Mail and Calendar apps for Windows 10. To fix the issue, please try each of the following solutions in order. Why not limit the caching to a more reasonable 1 year, if they need to access things outside of this, they can, they just have to click ‘view messages on server’ to do so. Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support.





Change the limit to 1 year, wait for the sync, check the size of the OST once Outlook confirms all sync has been completed. Now change the slider to 2 years and follow the same principal. Outlook has a hard limit of 50GB per OST, decrease the period of e-mails that get cached, delete the cache, and re-run the sync.