As always, when default buildings are
appearing it indicates a duplicate AFCAD file that should be removed
from your sim. Be sure to run the Flightbeam Manager's troubleshooting
tool to fix this in a few clicks.
Here are the steps in order to resolve other conflicts (in order):
1 - Use the Flightbeam Manager's troubleshooting tool to automatically find files causing this.
2 - If the above didn't work: Open your Scenery Library, start
unchecking scenery one by one to temporarily de-activate them until the
duplicate buildings disappear. This will tell you which scenery entry
has the problematic file.