I was wondering could not find the answer if I missed it somewhere let me know. I was wondering if there was a way to "lock" a color crystal in a saber where the saber is upgradeable in all slots except the color crystal.

If that is not possible then how can you make a saber or hilt unupgradable I would prefer to have the saber upgradeable in every slot except the color crystal.

I'm not sure if I understand. Since you replace color crystal saber model will be change with another saber model. More, that crystal put in any other hilt will be have as result changing hilt model to original one. If you want to not "lose" that cystal set in his .uti file "plot item" and it won't be available for sell or destruction. Same seting for his hilt.

I did not think about "plot item" I will give it a try.

I know that in KOTOR I, if you delete all of the upgrade properties from the 'properties' field in the saber's .uti file, it won't be upgradeable anymore. Say you wanted to make it so that all green sabers were unupgradeable; all you would have to do would be to wipe the properties. I don't know if that's what you were referring to, but I hope it helps.