It could be caused by a filter - click Clear and see if the data appears.
It could also be an out of date cache - does it say 100% for all sections in the status bar at the bottom of PT3? If not, run Database > Housekeeping with the default options.
What version of PT3 are you using?
If it isn't one of the versions on the download page please update:
Download pagePT3 Build History / Release Notes