Counterparty registered a set of new domains at dot-io (.io) so those who use various plugins or utilities that save passwords may think that their settings are "gone".
In that case it may be helpful to check if they're still available for the original domain (counterwallet.co) and use them to login to counterwallet.io (for those who use Easy Access URLs).
The two existing dot-co (.co) domains, counterparty.co and counterwallet.co, will remain active for a while.