[Lizard]

OmniFocus should delete the lock every time it quits, whether that's because you told it to quit, or because it's grabbing a Sneaky Peek update.

If you quit OmniFocus, delete the lock and then reboot your MacBook Pro, you get the error?

What if you turn off "Open at Login" for OmniFocus and then delete the lock file and reboot? Do you get the error immediately on login? Or when you launch OmniFocus?