ReadyNas 6.2 (NAS locks up entirely)

I have a 104 running the latest beta that continually freezes, sometimes after a day, then sometimes after an hour. It has been doing this for quite a while and i keep loading the latest beta version of the 6.2.x firmware to try and solve it, all to no avail. The only way to make the system usable again is to unplug the power cord and then power it back up, do you guys have any idea why it is doing this ?? This sort of unreliability was never around under 6.1 .. can i downgrade ? If i do, do i loose all my data ?? not ideal but i suppose better than the pita issue i have now? thoughts ??