Disclosed herein are methods for protecting user information on a client device that may have a plurality of users. A user interface with a public machine designation portion is presented to a user prior to the start of the authentication process. The public machine designation removes web service account descriptions and any user specific information stored on the client device. Also, the client device is prevented from storing any new user specific information that is provided to the client device. The public machine designation is a persistent feature that may only be disabled by an affirmative action from the user.