https://forums.autodesk.com/t5/revit-api-forum/loadfamily-fails-with-empty-drawing-works-ok-with-wall-already/m-p/5760040#M71143 Apologies - the saved 'blank' drawing already contained the loaded family and I didn't realise; hence, it failed because it was already loaded. Code now looks for the existing loaded instance and returns that reference instead. Thu, 06 Aug 2015 14:33:44 GMT Anonymous 2015-08-06T14:33:44Z https://forums.autodesk.com/t5/revit-api-forum/loadfamily-fails-with-empty-drawing-works-ok-with-wall-already/m-p/5759631#M71142 <P>I have an add-in that loads a custom work-plane-based family whenever a new document is opened or created.&nbsp;</P><P>&nbsp;</P><P>If I open a drawing that has a wall in it, LoadFamily() returns true as expected.&nbsp;</P><P>&nbsp;</P><P>If I open a drawing that has had the wall deleted (and then resaved, of course), it returns false. Curiously, though, it *does* appear to load the family - it is in the tree and as long as I choose the Level 0 work plane, I can insert an instance.&nbsp;</P><P>&nbsp;</P><P>Any idea what I'm missing? It seems the wall includes&nbsp;something in the drawing that loading my family needs?&nbsp;</P><P>&nbsp;</P><P>Thanks in advance.&nbsp;</P><P>&nbsp;</P> Thu, 06 Aug 2015 10:46:32 GMT https://forums.autodesk.com/t5/revit-api-forum/loadfamily-fails-with-empty-drawing-works-ok-with-wall-already/m-p/5759631#M71142 Anonymous 2015-08-06T10:46:32Z https://forums.autodesk.com/t5/revit-api-forum/loadfamily-fails-with-empty-drawing-works-ok-with-wall-already/m-p/5760040#M71143 Apologies - the saved 'blank' drawing already contained the loaded family and I didn't realise; hence, it failed because it was already loaded. Code now looks for the existing loaded instance and returns that reference instead. Thu, 06 Aug 2015 14:33:44 GMT https://forums.autodesk.com/t5/revit-api-forum/loadfamily-fails-with-empty-drawing-works-ok-with-wall-already/m-p/5760040#M71143 Anonymous 2015-08-06T14:33:44Z