Hey guys. Lately I got some problem with toolbox. After creating some parts using toolbox option, Lets say i save it as a file named "aras" into my desktop. I modify its look by using cut extrude and making keyways etc to make it exactly look like the gear i have. After that, I used that gear in an assembly and saved the assembly. But whenever I re open that saved assembly it says this assembly needs to be rebuilt and when u click into rebuilt button,instead of using my "aras" gear file, it replaces my gear file with the raw gear file from the toolbox system without any external modification (without keyways,or any other modification i made manually). I did not understand why this happens.. Any help would be appreciated.