I receive the following message when trying to import a .ics file that we
generate on our intranet.

vCalendar/iCalendar Import failed. The input file may be corrupt. The
function cannot be performed because the message has been changed.

But when Opening or drag and drop, it opens perfectly and can be saved.

Example .ics file is shown below
BEGIN:VCALENDAR
PRODID:-//GSM Association//NONSGML iCalendar file//EN
VERSION:2.0
METHOD:PUBLISH
BEGIN:VEVENT
DTSTART:20051212T090000
DTEND:20051212T120000
DTSTAMP:20060113T154422Z
DESCRIPTION:Meeting Details:
Meeting in Dublin........ Test

Reply By Date:
09-Dec-2005

Contact Details:
Organizer: R. Doyle
Company: GSMA
Address: Deansgrange
Dublin

Note:
Unless otherwise stated, the times shown are local to the following
location: Dublin

LOCATIONublin
CLASS:PUBLIC
STATUS:CONFIRMED
SUMMARY:Test Meeting
CATEGORIES:Business
ORGANIZER: CN=R.
CONTACT: R. Doyle,

END:VEVENT
END:VCALENDAR