This particular scenario occurs following an unsafe (forced) shutdown of a kiosk unit running Sitekiosk 8, either by forcing a blue screen error, or by unplugging the unit without executing the proper Windows shutdown processes. 

Sitekiosk uses a derivative of the Internet Explorer web browser engine, and this issue occurs due to the manner in which Internet Explorer commits its cookie data and related website information to a local .dat file during a safe shutdown scenario. When an unsafe shutdown scenario occurs, this commit process does not take place, resulting in Internet Explorer forgetting it's cookie data for when the browser is next opened. This behaviour is inherent within Internet Explorer and affects all website and web applications that rely on client-side cookies to retain login and session details, and is not limited to the Manhattan Space Scheduling Kiosk application.

Whilst it's not always possible, we would recommend avoiding any unsafe restart scenarios for your Kiosk units in order to minimise any end user inconvenience. If an unavoidable unsafe restart takes place, a member of staff would be required to refresh the web browser within Sitekiosk to recover from the issue. If you have a screensaver timeout enabled within Sitekiosk, recalling the Kiosk unit from the screensaver will also remedy this issue.