And I hate, hate, hate that MS decides to restore certain reg settings when I install security patches! GRRRRR!
I had the exact same problem and found this thread via Google a couple days back. Since then, I've tried lots of things and nothing worked. Now I've finally found the culprit. It was a registry hack from a website called Windows Central that removes Quick Access from the File Explorer. In the following registry path...
...the DWORD value "Attributes" was changed from a0100000 to a0600000. This takes care of the Quick Access folder, but also removes drag and drop functionality from the navigation pane. After changing Attributes back to a0100000, everything is back to normal. I'll just leave this here in case someone else runs into the same issue.
How about plain drag and drop, like on a web course I'm doing. I have to drag and drop the matching answer and I can't move the icons.
My attributes are a0100000 and it still would not let me DnD. I found a youtube video where someone said VMWare was not yet fully compatible with 10, but add the tools. I added VMWare tools and DnD works like a charm. Just registered to post my results.