Hello, I'm having a weird problem with solidworks 2017. I have a large assembly (that contains several subassemblies). I'm trying to use certain parts of it as a mockup in another assembly. What I would like to do:

1) copy the whole original assembly (call it assem1) to another location, so that I can mess around with this copy without messing up the original

2) copy the local copy (assem2) several times (to assem3, assem4, assem5), and delete certain components from each of them

3) combine these modified copies (assem3+assem4+assem5) into their own assembly

I know that I could accomplish the same thing by copying individual components, and redoing the mates from the ground up. However, I'd prefer not to have to do this, because it's just supposed to be a quick mockup, and all the mates I need are already in assem1.

Anyway, so here's solidworks' response:

-If I just delete whole subassemblies from assem3/4/5, everything works fine. 3/4/5 keep their separate modifications, and assem1 remains untouched

-if I delete parts of subassemblies from assem3/4/5 (using the graphic editor), it asks me the following:

I choose "delete selected components", because I want to delete just part of the subassemblies.

-I save, and everything is still working as I would expect at this point. I have deleted some parts graphically from each assem3, 4, and 5, and they all reflect these changes accurately.

-However, when I then make a new assembly with assem 3,4, and 5 together, solidworks starts doing weird stuff. It says it needs to rebuild, and then all the three subassemblies change to one modified state (the components I deleted from one of the three becomes the components deleted from the other two as well). Even more weirdly, these changes somehow snake all the way up to the original (assem1). Before this point, the original has remained unmodified. But after this rebuild, the components deleted in assem3/4/5 are also deleted from assem1.

This behavior occurs apparently independent of the way I copied the original in the first place. Neither pack and go, nor manually copying the files in the explorer protects the original. It even goes through copies of copies.

It makes sense that deleting only certain parts of a subassembly modifies the subassembly file. However, what I don't get is why the changes cascade to copies of that subassembly in an entirely different location. I would have thought that they would only change the subassemblies contained in the file I'm editing, but apparently not. And it's even weirder that it doesn't occur until I put assem3/4/5 in an assembly together.

Any ideas?