When eM Client 6.0.24144.0 imports an iCalendar with quoted mailto values, the following error is displayed: “Could not import file xxx.ics: The attendee address format is not supported. The file will be skipped.”
The sentence “The file will be skipped.” is inaccurate because events before the bad one are imported. It would be helpful to display more information about the incorrectly format event so that the user can find and correct it. It would also be helpful if the user could choose to abort the entire import so that re-importing the corrected file does not create duplicate events.
The .ics file was exported from Thunderbird 38.5.0. There were two events with ROLE properties that had quotes around the mailto values. Here is an example.
ATTENDEE;RSVP=TRUE;CN=John Smith;PARTSTAT=NEEDS-ACTION;ROLE=REQ-PARTICIPAN T:mailto:"email@example.com"
I’m not certain, but I believe that the Thunderbird export should not have had quotes around the email address, or at least escaped them (I believe the event was originally sent with these extraneous quotes).