Vista betas to expire on May 31
From May 18 users will receive warning notifications notifying them of the expiry date. After the expiry date, customers who continue to use pre-release versions of Windows Vista will be able to log in for 2-hour sessions to retrieve data. After 2 hours of use, the PC will automatically reboot without providing the opportunity to save data.
To avoid work disruption and loss of data, we strongly recommend that customers running any of these pre-release versions of Windows Vista migrate their PCs to the final version of Windows Vista prior to 31 May.