OK.. maybe it was pre 2.6.2 actually.. It was pre-5.5 nodecanvas serialization I was upgrading from? @autorun isn’t a prefab. I had previously fixed all the prefabs.. those actually showed “components” with my graph objects on them on the prefabs. I was able to remove them with “remove component” in the editor. manually.. hundreds of them 🙂 Until I did that, Unity would just crash when you saved the scene (but not when saving to another filename!). This scene was the exception.. but I went back to 5.4.5 and ran my utility script I wrote that would automatically bind and validate the graphs back to the graph owner objects. Then I exported a package with that scene and imported it back into 5.6.4. Thankfully most of those errors were gone except 8 of them. For those 8, the graph object “components” were hidden on objects that didn’t even have a graph owner component.. probably the designers copy and paste of unity game objects? So I manually recreated those objects and all seems to be working.. fingers crossed 🙂