I guess that when your in 3D and you click on load material file and select, there is no going back to your previous setup?
You can save your current settings by selecting File⇒Material File⇒Save and give it a name. I generally use the name of the current project. Then you can switch back to it by selecting the name from the list.
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I'm pretty sure you can do and "Undo" to get back to your last material file. You'd have to do it as before you made a lot of changes or you would lose them too.
Yep, good call there Phil. I'm pretty sure this only works in 2014 since undo for materials changes did not exist in previous versions. I knew you could undo a few materials editing changes but I didn't realize you could undo changing the material file as well.