Issues Importing Calendar (mozilla Thunderbird)

I recently downloaded the latest version of Thunderbird ( 45.1.1) and installed the Lightning add on. I had the same set up at work, both on Windows 10. The saved calendar I have is from 7/15 and I believe I had Windows 8.1 when I saved it. I no longer work there to export a more recent .cvs file. I didn't save a .ics file at the same time unfortunately. Just the .cvs

When trying to import the .cvs file into Lightning, nothing at all happens. I searched pretty extensively for an answer but I'm getting frustrated. I tried uninstalling Tbird and re-installing already too.