Hi everyone,

Recently I upgraded from sw2019 to 2020 sp1 and I have a project in c# that run correctly with sw2019 but after I uninstall 2019 version and install new version 2020 and Removed the COM Object SLDWorks 2019 and add 2020 in references of visual studio in solution tree and replace these dll files with new one at "C:\Program Files\SOLIDWORKS Corp\SOLIDWORKS\api\redist" path (sw 2020 installation directory) in the references as you can see in the screen shots :

SolidWorks.Interop.cosworks.dll

SolidWorks.Interop.sldworks.dll

SolidWorks.Interop.swconst.dll

unfortunately some function still uses the 2019 directory and it seems somethings gone wrong in using 2020 api and there for the model is not creating correctly(missing part template and ...) and all code not run ! how ever swApp = new SldWorks.SldWorks(); made the Solidworks 2020 to run and I can see the window open but then it trapped in error for creating model at first step ! ... can any one tell me Where am I wrong ?

my sense told me I made a stupid mistake here but I can't find it ...