If you're having to reinstall, it's because you cut off the patch in the middle, corrupting the process.
It's converting the patcher to the same type as the EC.
As long as you let the updates run its course (the DOS window is part of it), then let the updates run their course without UOA running, it updates fine. Note that this patch comes in multiple parts. Only when it says it is up to date on startup without patching, without using UOA to start it, is it really done.
UOA has two issues with it.
1. IT starts UO with both the client running, as well as the new patcher (if you're patched up, just close the patcher)
2. For some reason, the patcher that starts with UOA running keeps repeating the last patch, which was completed properly. In other words, if the new patcher starts downloading gumpartlegacyMUL.uop over and over, just ignore it and close it either before it starts to install, or after it reinstalls (not DURING), and use the client that shows up IN ADDITION to the Mythic patcher.
BTW, I can't get where people are getting the "minutes" for the patcher to run - if you're fully installed, it takes 15-30 seconds. I ran it TWICE in a minute, and I'm on a pathetic old laptop with an old wireless router, with about 60-80 latency to both coasts. Now, if you let it run through the reinstall of an unneeded file, it might take that long, otherwise, it's run faster through those new patcher installs than through equivalent sized patches in the old one.
The new patcher has one advantage, once the bugs get worked out of it and Tug fixes UOA for it... If you miss several patches in the future, it will apply all of them in one pass, instead of multiple patches.