Gerald,
This happens occasionally with the last few versions of the Loader Program.
What works for me is to disconnect the cable between the TIU and the PC, power cycle the TIU and reconnect the cable.
Then, Search for the TIU from the Loader Program's Options tab.
If that doesn't do it, disconnect the cable between the TIU and the PC, power the PC and the TIU off and then on, reconnect the cable, and do the Search.