If Windows 10 still has it, make sure you run the shortcut for Razor that you use for UO with Administrator turned 'on' and compatability mode set to 'Windows XP SP3'
That should be about it. Any other weird stuff let us know, might be good for others going through the same install.
I converted to windows 10 maybe 5 months ago, and recently starting playing UO again. I've been having trouble where my PC completely freezes, and I have no choice but to do a hard reset or hard power off. The freeze does not particularly appear to be related to duration (I only play a couple hours a day max), though something tells me it happens more often if I have more than 1 client up. I've followed the recommendations on this thread, (except I am not sure what Aero theme is). I have also googled quite a bit, and found things like going into the Link State Power Management and turning it OFF. My PC is clean; I don't have this issue except when UO/Razor are running. All of my drivers (especially graphics) are up to date. I've done a registry check and removed issues... all recommended through google searches.
I am at a bit of a loss - any guidance would be greatly appreciated. (I even looked into switching back to windows 7 but it is too late, and I am not comfortable performing a clean install myself).