How to load a previously saved Sim without previous traits/achievements

@Simone_inatorulWithout using a mod, that's not possible. However, if you have the EP Get to Work you can get the cloning machine and if it's upgraded you will be able to create a clone that is added to the family. (Not an exact copy though and it can turn out to be evil).

If you don't mind using mods, you can download a mod called MC Command Center, you can use it to make an exact copy of your sim sans skills, traits, achievements etc. It even copies all the outfits and such with the exception of the makeup. Apparently, that's not possible.