Hi Henry,
Everything Mariano says is true. Like Richard said, you will probably not experience any problems with day-to-day transactions entered from the user interface. I have had problems in the past of corruption of the passwords. Or, better put, Dynamics could not interpret or 'unencrypt' the password. Easy to fix, but a fix that is unnecessaryif the problem can be prevented.
My advice, uncheck the box,
Kind regards,
Leslie