It happends very often, Prey process takes all resources and CPU goes to 100%. The only solution I found is to reboot my computer until it happens again...
I have 2 macbook pro, one with Yosemite (10.10.5), the other one with Mavericks (10.9.5). I have the latest prey version (1.6.9) on Yosemite and 1.6.8 on Mavericks. It happens on both computers.
If someone has an idea on how to solve the problem, it would be great.