It works fine here.
UAD plugins show up under “plugins” as the second choice below “process” from the “Audio” menu.
Did you trash Prefs when you un/re-installed?
yes headlands, i had the same problem with one of the uad neve plugs and offline processing.
I just gone with a waves eq and never thought about it but i will test it tomorrow again. In my case the audio file is erased after processing.