Mike Rife
Ansys Employee

Hi chonkian.lee

Ok please review the Ansys Workbench Help; Working Through a System; Component Systems; External Model.  There are a lot of links to follow w.r.t. differing topics of this.  So also check any warnings/errors that Workbench, External Model, or Mechanical might have issued for clues.  Also which version of WB are you using?  I suspect that maybe the dat file has very little content and instead inputs some other file(s).  If so maybe the version of WB that you are using does not support that type of input file nesting.  MIke