Hello CadLib Team, When importing Xref enabled dwg files from AutoCAD, our application has a feature that reads the dwg file using cadlib dlls and saves the parent child relationship link details in our table. It works up to AutoCAD 2013 version, this feature doesn't work in AutoCAD version 2020. When reading the dwg file it throws an error as Exception has been thrown by the target of an invocation. Please check the issue .We have attached the DWG file(created from AutoCAD 2020) .PFA. Looking forward to your reply soon. P1.DWG : parent document C1.DWG : child document. Thanks & Regards, Able M Peter Wrench Solutions Pvt Ltd