I have a calculated field I would like to edit, but Tableau will not let me edit it, how can I overcome this? It will not let me delete it either. It will only let me edit a copy of it, which is fine, but cluters up the measure with fields I do not need. I have attahced a picture below showing this.
Unfortunately your screen shot cuts off the data source. Are you connected to a published Tableau Server data source? If so, you won't be able to edit it.
Here is an even better answer: