Q:

Outlook iCal does not work? 

When an activity is assigned to a user and an email is sent to the assignee with the calendar appointment, the ical is attached.  However, when I open the file in Outlook 2013, it says "Meeting cannot be found in the calendar."  I'm unable to save/add the meeting date into my calendar.  Is there a way to resolve this?  
I've also tried the activity iCal module, and I haven't been able to find a solution to add activities to Outlook effectively. 

A:

I think this is resolved.  After researching prior problems with icals, I found this reference: https://stackoverflow.com/questions/15084236/icalendar-does-not-create-an-event-for-organizer 
By changing the METHOD: REQUEST to METHOD: PUBLISH in templates/CRM/Activity/Calendar - Outlook users are essentially inviting themselves to their events (and the possibility to including others who are not Civi users). 
Note: However, it looks like the notes aren't being pulled into the ical, and I'm not sure if this should occur or not.