I have used the "Save As" command many times in the past, without problems. I have made about 15 incremental copies of File-1, in order to make design changes to the model; that way I can fall back to the saved copy, if needed. The only difference with File-2, is that I "moved" the groups back to layer0. I did this to purge and clean up the model before starting the rendering process. I have not started the purge and file cleaning process, however, I did explode the whole model once it was on layer0. I have a problem with posting the 3d design model file; because the model is a house design that will be for sale. Intellectural property (copyright)thing. If there is a way of posting my designs on the forum without losing my rights to the design; I would love to share then with the members. TIA, Bob