Cannot load families into project, getting A serious error has occurred message

[Anonymous]

I have tried several families including some I have used in the past. None will load into project. I get the message: A serious error has occurred, It is strongly recommended that you save as to save your work in a new file before continuing.  

[Revit_Whisperer]

I was able to open the file and load an out of the box door family.  I unloaded the cad link so you can test opening this file and loading a family in case the link is causing issues, or it could be one of the specific families you are trying to load.

[Anonymous]

I could not open the link. However I recalled that I had changed the graphic display options to smooth lines with anti aliasing before trying to load these families. After unchecking this box I was able to load a family for the first time. Anyone have any opinions on why this might cause this problem.