After upgrading my Mac to Sierra, Prey stopped working
With macOS Sierra, Apple made some changes to the system and that messed up several apps including Prey.
There are two simple ways to fix this. One easier than the other, but still… both of them solve the issue in the end.
You can whether reinstall Prey into the Mac computers you’ve upgraded to Sierra https://preyproject.com/download.
Use this patch
Download this link and the problem will be immediately solved. Just install it and everything will be back to normal.