Also -

 

What is this .CKT file you keep talking about?

 

Presumably your SPICE model for the part is in the .LIB file, and only in the .LIB file.  If that is the case, then the .CKT file is not part of the model.  Maybe the .CKT file is something needed by PSpice or some other simulator.  LTspice doesn't need that file.

 

I'm not saying that LTspice never uses a .CKT file.  If the part's SPICE model was in the .CKT file, then that is the file LTspice needs.  It doesn't care what is the filename extension.  But because you also have a .LIB file, chances are very good that the .LIB file is the SPICE model and the .CKT file is not.

 

It would not be unheard-of to have parts of a model in both files.  Very unusual, but not impossible.

 

The best way to tell is by looking at what's inside each file.

 

Andy