I'm using ArcGIS 10 SP2 and I encountered a problem with the join table tool today (9/9/11). This problem occurred when rerunning the model from the model builder window, not when running the model from the dialog that opens when you double click the model in a toolbox. My model crashed downstream of the join tool due to an error of mine in the calculate field tool. So I closed the dialogue that prints all of the data from the geoprocessing model as it runs and returned to the model builder itself. I corrected the error in the calculate field tool and validated the model so I could re-run it. But the join tool and everything downstream turned white - indicating an error at the add join tool. I double clicked the add join tool and the red error symbol was present in the add join dialog box. When I hovered over it, it reported that the join table was already joined to the target feature class.
It seems to me that the validate model process doesn't clear out joins from previous sessions. I think it should. When you validate an entire model, it's going to run from the very beginning next time that you run it. So shouldn't model builder detect this and remove all of the joined tables as it validates the model?
I also tried saving, closing, and rerunning the model - no dice. So I closed and restarted ArcCatalog, thinking that something in memory was hanging onto the join. No dice. Then I added the remove join tool immediately upstream of the add join tool and that worked. Of course, I had to remove it for subsequent runs of the model. This seems like a bug to me, but maybe I'm missing something. I hope this helps anybody who is encountering a similar issue.
