Whilst trawling the GIS SE site I became aware of something called Attribute Assistant, an add-in that had some clever attribute assisting functionality. I have downloaded it and installed it, believed I had created a sensible rule then ran it. It bombs out Arcmap with object not set. So thinking I had not done something correctly I reviewed what I did, still thought it was OK but then tried to turn off/on the add-in using the button on the tool bar. Button goes red and shows this error:

This immediately makes me think that this add-in is not compatible with 10.4.1 and would explain why I could not run the generate ID rule. I am using Windows 8.1. Can someone from ESRI confirm this? Are there any intentions of making this 10.4.1 compatible?