Opening ICS file with multiple events creates new calendar in Outlook : <p>I would like to be able to create an ICS file <strong>with multiple events</strong> that user will be able to import in their <strong>default</strong> Exchange Calendar. I need to support Outlook desktop client, Office 365 web interface and Apple iPhone Mail/Calendar. </p>

<p>Note that issue only occurs with ICS files that contain multiple events. Single event ICS works as expected.</p>

<p>Following multi-event ICS file:</p>

<pre><code>BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//bobbin v0.1//NONSGML iCal Writer//EN
CALSCALE:GREGORIAN
METHOD:PUBLISH
BEGIN:VEVENT
DTSTART:20180327T080000Z
DTEND:20180327T110000Z
DTSTAMP:20091130T213238Z
UID:1285935469767a7c7c1a9b3f0df8003a@yourserver.com
CREATED:20091130T213238Z
DESCRIPTION:Example event 1
LAST-MODIFIED:20091130T213238Z
SEQUENCE:0
STATUS:CONFIRMED
SUMMARY:Example event 1
TRANSP:OPAQUE
END:VEVENT
BEGIN:VEVENT
DTSTART:20180328T120000Z
DTEND:20180328T130000Z
DTSTAMP:20091130T213238Z
UID:1285935469767a7c7c1a9b3f0df8003b@yourserver.com
CREATED:20091130T213238Z
DESCRIPTION:Example event 2
LAST-MODIFIED:20091130T213238Z
SEQUENCE:0
STATUS:CONFIRMED
SUMMARY:Example event 2
TRANSP:OPAQUE
END:VEVENT
END:VCALENDAR
</code></pre>

<p>works fine in Office 365 web interface and Apple iPhone Mail/Calendar. However, when it is imported in Outlook 2016 it creates a new "Untitled" Calendar and puts events in it instead of default user calendar.</p>

<p>This seems to be a known issue referenced previously on SO:</p>

<p><a href="https://stackoverflow.com/questions/9212329/ical-import-creates-new-calendar-when-open-the-ics-file">ICal import creates new calendar When Open the ics file</a></p>

<p><a href="https://stackoverflow.com/questions/21484689/have-ics-file-with-multiple-events-save-to-my-calendar-not-other-calendars">Have ICS file with multiple events save to my Calendar, not Other Calendars</a></p>

<p>Answers range from "it cannot be done" to the opposite.</p>

<p>One of the posts in the first link mentions removing  <code>X-WR-CALNAME</code> from ICS fixes the problem. I never had this in ICS to begin with.</p>

<p>Another post on the same page mentions that adding <code>X-WR-RELCALID:XXXXXX</code> fixes it. I tried putting it in and it makes no difference at all. I am not sure if value for X-WR-RELCALID should be set to something specific - I just set it to some GUID.</p>

<p>If someone successfully resolved it - can you post an ICS sample and what version of Outlook did it work with?</p>
