Comment 15 for bug 880703

Seems I found a workaround. When starting Evolution from console I saw an error message saying that ~/.evolution/tasks could not be deleted. That dir was empty. I deleted it, shutdown Evolution (some process hung after rmdir ~/.evolution/tasks, killed them), started Evolution, it then said "Migrating cached data, Migrating config data, Migrating local user data". I could then accept an invitation and save it to my personal calender where it now appears in. I don't know whether this solved the issue permanently or if it will recur.