After transferring emails to EMC I got five error messages popping up every time I open program. Read in forum to repair folder which I did more than once in fact I have repaired every folder in em client. Still occurs when open and when sync. Here is screenshot: 
Hello, I’m afraid this is caused by an invalid calendar item in your calendar, try to repair your calendar items, by right clicking the folder in the left pane, navigating to it’s “Properties” and select the Repair tab, use the Repair button to resynchronise the folder with the server, this should remove the invalid item that includes the invalid organizer format.
Hope this helps,