A strange combination of problems
I've got two problems that may be interrelated.
One. Daz Studio's interface is completely white after I've upgraded to 4.8. I can see text, but almost nothing else is visible.
Two. Install manager says that Daz Studio 64 bit isn't installed. It shows as a product I can download, but if I run the install the same problem occurs. The next time I start the install manager it says it's available for download and doesn't show up as installed.
What can I do?

Comments
Did you have your previous version of DAZ Studio running while installing? That always causes problems.