Problems with mouse
This can be solved for some clients by setting "MouseThread=off" in every uo.cfg (there are many for each character and one global).
Problems running uo.exe
You can safely use client.exe for the game and run uopatch.exe from time to time manually.
Connecting to free shards
You have to disable encryption for your client:
- Either you can find already patched client for your shard (browse the shard forums). And you can run it like the normal one (tested by Plague).
- Or you can patch the client yourself using UO Rice (some say this can be only done on Windows and before any patching) and then run the patched client. (suggested by sk8dork, not tested by Plague).