A private Ultima Online shard
Windows · about 73 MB · free
It will, and nothing is wrong. The package is not code-signed, so Windows does not recognise it.
A blue "Windows protected your PC" box: click More info, then Run anyway. An "Open File - Security Warning" box: click Run. If antivirus quarantines something, restore it or unzip the package again.
If you would rather not click through a warning you do not understand, ask first.
"Cannot reach Shattered Legacy" means the server is not answering. It may be restarting. Wait a few minutes, then say something if it keeps happening.
"Couldn't connect to Ultima Online. Please try again in a few moments", right after typing a new account name, is not what it sounds like. Waiting will not fix it. Say something and it can be sorted out in a minute.
Anything else: a photo or a screenshot of the window is worth more than a description.
The game client is TazUO, a free and open-source Ultima Online client, under the BSD 2-Clause licence. The rest is a few small scripts that point it at this shard and start it.
Nothing from EA is included. Ultima Online itself comes from EA's own free installer at uo.com, which the package fetches for you if you do not already have the game.