Edit: Both addons I was mentioning have had updates for the new patch and work again.
I am leaving the part about how to remove / disable addons in as it might yet prove useful in the future.
To disable user addons there's 2 options:
1. Permanently remove.
- WinKey + R to open the run dialog, then type %appdata%\NCSoft\WildStar\Addons and press Enter.
- Remove the SteadyPlates addon folder (as an example)
- Restart the game or if you were already playing /reloadui
2. Temporarily disable.
- From in-game, Esc to show config sidebar > Click Addons
- Find addon in list select it and press "Change Load Rules" button.
- Set it to "Do Not Load Addon" and x it.
- Press the ReloadUI button at bottom right.