If you are using iCal then you inevitably have come across problems (errors) when importing .ics or .vcs files you may receive via email. Almost all calendar invites from Microsoft fail to import into iCal (at least for me). The good news is that you can work around almost any import problem. The bad news is that it takes just a bit of grunt work (I am working on a solution for that too).

What is the problem?

Surprisingly Apple is not adhering to the iCalendar specification. Apple's web site (http://developer.apple.com/internet/appleapplications/icalendarfiles.html) will point you to the Internet Engineering Task Force site where the specification lives (http://www.ietf.org/rfc/rfc2445.txt)

1. The iCalendar specification states that the property and parameter names are case-insensitive (unless specifically noted) while Apple appears to require them to be upper case.
2. Apple also does not appear to like a space following the property colon.
3. Apple requires VERSION:2.0 and will not import VERSION:1.0 files

The fix is quite simple:

1. Change all property and parameter names to upper case.
2. Remove the space after the property colon
3. Change the VERSION to 2.0
4. Sometimes is helps to rename .vcs files to .ics

This alone has cleared up over 98% of my issues.

If you are still having problems here are a few more tips:

1. After an import fails, open the Mac OS X Console application; select DATABASE SEARCHES -> Console Messages and look for iCal errors. Console can be found at Finder -> Applications -> Utilities -> Console.
    1a. If the Console reports that a property or tag is invalid then simply remove it - which might also include a closing tag and all of the content in-between

2. Verify that you did not introduce any typos into your converted file by validating it at this web site: severinghaus.org/projects/icv/ />
3. I am working on a utility (it will be free) that will automatically correct these problems.

Hope this helps and happy iCal'ing!

Example Before (TrainingEvent.vcs)

BEGIN: VCALENDAR
VERSION: 1.0
BEGIN: VEVENT
DTSTART:20100324T190000Z
DTEND:20100324T200000Z
Location;ENCODING=QUOTED-PRINTABLE:
DESCRIPTION;ENCODING=QUOTED-PRINTABLE:Sponsored by NaviSite, Inc. and SaaS-it Consult, in conjunction with Microsoft, this one-hour webinar will give ISVs and application developers the opportunity to learn more about the benefits of SaaS, Managed Hosting and Managed Cloud Services as a future business and IT delivery model. The webinar will also include key factors to include when you evaluate your ISV business and how it will fit into the new era of IT delivery. =0D=0A=0D=0AAttendance Url: www.msdev.com/Directory/Description.aspx?eventId=3D1764 />SUMMARY:SaaS As a Business and IT Delivery Model - Webinar Event Sponsored By: Microsoft, SaaS-IT Consult, and NaviSite
END: VEVENT
END: VCALENDAR

Example After (TrainingEvent.ics)

BEGIN:VCALENDAR
VERSION:2.0
BEGIN:VEVENT
DTSTART:20100324T190000Z
DTEND:20100324T200000Z
SUMMARY:SaaS As a Business and IT Delivery Model - Webinar Event Sponsored By: Microsoft, SaaS-IT Consult, and NaviSite
DESCRIPTION:Sponsored by NaviSite, Inc. and SaaS-it Consult, in conjunction with Microsoft, this one-hour webinar will give ISVs and application developers the opportunity to learn more about the benefits of SaaS, Managed Hosting and Managed Cloud Services as a future business and IT delivery model. The webinar will also include key factors to include when you evaluate your ISV business and how it will fit into the new era of IT delivery. =0D=0A=0D=0AAttendance Url: www.msdev.com/Directory/Description.aspx?eventId=3D1764 />END:VEVENT
END:VCALENDAR