Did the hands import for the other sessions?
Have you selected your screen name in the player list on the left? If you haven't configured "My Name Is" in the
Settings Window then it won't select you automatically when you start PT3. (apologies if that sounds obvious, but it has been the problem sometimes.)
Other than that, have you created a new database? If you have auto import configured to import to a database which isn't Active you won't see the results unless you switch to the other database.
Tutorial: Using Auto ImportIf none of that explains it please enable logging, restart PT3 and play about 20 or 30 hands at a single table with auto import running and then Refresh the Sessions tab and attach a screenshot of it along with the PokerTracker.log file to a support ticket so that we can investigate further.
Tutorial: Submitting a Bug Report