Genesis showing up as ‘cubes’ implies that it’s having trouble finding the Genesis geometry. It’s finding the high level figure file okay, but the actual geometry is missing. (Don’t panic, it’s probably not actually missing, it’s just your configuration isn’t pointing to it for some reason.)
So… If you have DAZ Install Manager, bring it up. Go to the second tab (‘Ready to Install’), and down at the bottom make sure ‘Show details’ is checked. There should be a label: ‘Content Files Install To’.
Now pull up DAZ Studio. Go to the Content Library tab, and up at the top should be an icon with a right-pointing solid arrow and four horizontal lines. Click that. That’s a sort of ‘context menu’ for the tab. Down from there is ‘Content Directory Manager’. That’ll bring up a new dialog. Use the disclosure arrow (right-pointing arrow) to open up ‘DAZ Studio Formats’. Now make sure that the path listed in DAZ Install Manager’s ‘Content Files Install To’ is also in the ‘DAZ Studio Formats’ list.
If that’s not, then add it to DAZ Studio Formats by clicking the DAZ Studio Formats row, then an ‘Add’ button will appear on the left. Click that and put the path in.
If the path DOES exist in DAZ Studio Formats, then it may have gotten installed wrong.
In DIM (DAZ Install Manager) go to the Installed tab. Search for ‘essentials’. There should be at least three, I think. ‘Genesis Starter Essentials’, ‘Genesis 2 Male Starter Essentials’, ‘Genesis 2 Female Starter Essentials’. To the right of Genesis Starter Essentials is a right-pointing arrow. Click that, and one of the options will be ‘Show Installed Files…’ Click that.
In the resultant dialog, at the VERY top should be ‘Content (...a path…)’; make sure THAT path is in your DAZ Studio Formats list in DAZ Studio.
Below that top line should be a long list of files. You don’t need to focus too much on those files, just quickly scroll through it and see if any _aren’t_ marked in blue and underlined. If they aren’t, then that means that file is likely missing. Too many of those, and I might suggest uninstalling and re-installing.
I hope this helps. I’d provide screenshots, but this forum software makes those not very helpful. :(