Might be above your pay grade, so I'll post and bug report:
If you have a medium to high end machine
&
Windows 10
&
quality graphics card
when faced with the question during a completely fresh install of DDO
"Do you want to download the high rez version of DDO?"
If you say "yes" the install will later ask
"Your machine seems capable of running Direct X 11"
If you again say "yes"
then the install seems to always work.
If you say no to either question, particullary the first one, the install will bug out badly and crash upon logging in
or go continuous busy blue circle forever.
Tried both ways more than once, on more than one machine till I finally saw the pattern.