Choose the File drop-down menu and highlight Save Calendar.Note: It is recommended to follow the guidelines sequentially to avoid any kind of data loss while exporting Outlook 2019, 2016, 2013, 2010 calendar.

Lightning is a Mozilla Thunderbird add-on that enables users to schedule group meetings, assign the tasks and appointments. Here, we are going to use Thunderbird Lightning to import Outlook calendar to Thunderbird. Method 1: Transfer Outlook Calendar Events to Thunderbird Using ICS Format Learn How to Import PST to Thunderbird?.A Guide on How to Sync Outlook Calendar to Google Gmail Calendar?.Read this answer in context 👍 0 All Replies (5) Note the download page for both parts also list a support email. Or perhaps you might want to ask the exchange active sync people here.

Perhaps you might want to ask in their support about your issues with that, which is given on the download page as You mention EAS and Thunderbird does not support that natively. I am guessing your calendar is provided via an addon. This is the standard properties for a calendar from the right click menu. Generally calendars are synced every 30 minutes and if they are calendars with thousands of entries may be quite slow and impact Thunderbird's responsiveness. Network latency poor internet firewalls VPN's and security software all have detrimental impacts on how long things take to be done. Try 10 minutes and see if you are still having issues with syncing. A home internet connection to a remote server will be very unlikely to complete a mail check, or a calendar sync in one minute.

Thunderbird calendar sync