I was having trouble with DS4 loading SecondLife avatar files, so I upgraded to 4.5. Downloaded and installed both 4.5 and the genesis essentials.
Now I have the same problem as the OP - no usable menus, and no keyboard options from them. I’m also on Mac, but I’m still running OS 10.5.8.
I have the Studio, File, Window and Help menus, but File is empty, with no dropdown. So I can quit, or look up help. That’s it.
I’ve reinstalled twice, with no difference.
Not only that, but DS4.5 can’t find My Library files (installed where the installer wanted them ), won’t load a figure directly from the My Library files, If I move the library folder out of documents, I can load a figure made of blocks, but it crashes almost instantly after I try to move a joint.
So, now instead of a DAZ Studio with a few minor problems, I have no working program at all. 
Chrys