We have released a new version of SETI@home based on BOINC, a general-purpose platform for distributed computing projects. We encourage you to switch to the new SETI@home. If you have problems with the new version, you can uninstall it and reinstall the old 'Classic' version of SETI@home. The schedule is:

On 14 May 2004 we made a 'snapshot' of SETI@home Classic user information (accounts, teams, profiles) and used it to initialize the new SETI@home database.
On June 22 2004 we made SETI@home/BOINC available for general use. There will be a 'transition period' during which you can run either SETI@home Classic or SETI@home/BOINC. During this transition period, SETI@home Classic accounts and team changes can be made, but they will not be carried over.
Once SETI@home/BOINC is running smoothly and versions are available for most platforms, we will turn off the data server for SETI@home Classic. At this point you will need to switch to SETI@home/BOINC.


http://setiboinc.ssl.berkeley.edu/sah/transition.php