I've just done my third install, this time on a completely fresh Windows 10 install, to try to figure out why the static timing analysis report appears to be corrupt, yet nobody else seems to be having the problem.
It seems that if the destination directory is one of the parallels shared folders (in my case my Documents folder) then the creation of the static timing analysis report gets corrupted and won't render at all in any browser.
If the destination (i.e. workspace location) is on the normal C: drive, then all is fine.
I presume the software that writes the timing analysis uses some kind of filesystem feature that isn't implemented in the Parallels remote filesystem mechanism (I saw a similar thing with the Xilinx tools some time ago) ... everything else works perfectly, it's only the timing analysis.
At least now I have a workaround when I need to do some timing work (i.e. copy everything to the C: drive), but it would be good if this was resolved.