Import Outlook Calendar Item Into Google Calendar, .ICS Import
If you use Google Calendar as your primary calendar for work the chances are that from time to time you receive calendar items from people using Microsoft Outlook. These calendar items which are sent as .ICS files are easy to import into Google so you don’t have to manually type the entry into your Google Calendar. Follow the directions below to import Outlook calendar items into Google Calendar.
**NOTE: If you are using Thunderbird to copy/paste iCalendar items into ICS files and then import into Google Calendar you will more than likely receive an import error. Please read this article for a resolution to that issue. The error will say “Failed to import events. Could not upload your events because you do not have sufficient access on the target calendar.” This may be a problem with other mail clients as well but I have only confirmed it to be so with Thunderbird.