I encountered an interesting bug lately.
My son has been bugging me to play DDO for awhile now, so I thought I'd give him one of my alt accounts to play around with.
I took one of my USB copies of the game, updated it, and then file copied it to his machine.
I have done this many times before when I ran multiple machines when I wanted to avoid doing the update more than once.
So I copied the files, loaded the game and it kept crashing to desktop after "loading data" just before character select. Just as the screen changes. I think that is the handover point from Launcher to the DDO game exe.
So I Googled, checked Turdbine Support and tried all the fixes I could remember. nada.
Went back and installed all the legacy .net shit. Checked the DirectX12 files were there.
Checked firewall permissions.
Gave each of the key Turbine .exe files admin privileges.
This is a brand new, mid tier machine with fresh install of Win10, lots of RAM, SSD and good vid card.
Deleted all the files, re-downloaded the game from DDO website, installed and started playing. This time I got to the character select screen, chose character, crash. Every time.
Rinse and repeat a dozen times after a reboot and rechecking all settings.
Tried running the game in DX9, DX10 and DX11 modes. No change.
On a hunch, ran the game from the USB stick - and it worked flawlessly!

What the heck?
Any ideas why it would run without a problem from a USB stick and not from the SSD?
The only thing I have noticed is that the SSD based launcher version prompts a a few UAC security permissions dialogues, but the USB launcher does not?
Could it be a Win10 UAC quirk that does not apply to USB sticks?
I have to say that I have had very few problems running DDO from USB sticks on many different computers.
So if you're having problems running it, copy all of the DDO Unlimited folder onto a USB2 or 3 stick and try running it. Might help diagnose the cause of your issues.