I saved an iCalendar file from my Outlook calendar, I went to tools/import in Thunderbird. I am at step 3 which says, "Select the ICalendar (.ics) file yu would like to import." Te first time I did this step, I selected the file and almost immediately I saw the results. But, then I thought maybe I wanted to increase the date range of my Outlook calendar. After doing so, I went back to tools/import in Thunderbird to import that file. Now, when I do that at step 3, Thunderbird seems to "freeze." I see no results for the iCalendar having been imported. If I wait several minutes, Thunderbird now allows me to go to my mail tab, but I still no import of my Outlook calendar. What did I do wrong?