how do i stop
 

How do i stop people from using charachters such as !@#$%^&*()=+ in there names because then when they have the .htaccess url on their profile it wont work because its going to be invaaled and i want to stop this from happening.

User Registration Options > Illegal User Names> Put in ! @ # $ % ^ & * ( ) = +
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but i want ti to have a custom error as well, like you can nnot use characters such as.. *(*)) or sometihng like that, it just says the name was taken.