I'll describe that in detail, first of all, I've restored the database and site content to a working 2 March 2014 backup 3 times to verify this.
I have a 6.x site that was using a very old 5.x era skin. It upgraded fine and was like a wisdom extraction to get all the old 5.x era skin out of the site. That done, Dark Knight was installed on it and it works now, fully.
Websites Creative has a great skin, Generic, that I have a trial of. Tried installing it but then, the menu functions for the main part of the site worked but navigating to Host or Admin areas stopped working. It isn't their skin, I've removed the content folder entirely, put the 2 March backup of it back in play, fully restored the DB.
Dark Knight of course is there and working. As soon as I set the skin to Gravity (or any DNN provided 7.x compatible skin), via Admin | Site settings, the same thing happens. I can't navigate by using the Host or Admin links in the top menu. I can browse by typing /host/hostsettings or /admin/sitewizard, etc. and get to those respective pages but nothing happens when I use any of the functions.
Browsing to /admin/sitesettings and trying to set the skin back to Dark Knight, definitely selecting "Update" does nothing. The skin will stay at whatever it was -- WSC Generic, Gravity, etc. Dark Knight or another skin / container can be selected but after Update is clicked, the settings don't persist.
It APPEARS complex but can't be. Again, the content was deleted and restored, db overwritten and the site comes back up. All Nav functions for Host and Admin again work.
There almost has to be an omitted, obvious step in the upgrade process from 6.2 to 7.x. I did upgrade, per Chris Hammond's site I believe to 6.8 and then to 7.x. This went incredibly smooth with no breaking changes to any modules, which is what I really feared.
The only issue is the one mentioned here. I've tried everything I can think of but haven't stumbled on the solution yet.
Thanks for any help.