[Lizard]

DannyG, could you try something? Quit OmniFocus and go find where your OmniFocus file is stored on your computer (usually in Users/[your user name]/Library/Application Support/OmniFocus). Right next to it there's probably another file named OmniFocus.ofocus.lock. Delete that file and then launch OmniFocus. Does the error message still occur?

Originally Posted by Lizard

DannyG, could you try something? Quit OmniFocus and go find where your OmniFocus file is stored on your computer (usually in Users/[your user name]/Library/Application Support/OmniFocus). Right next to it there's probably another file named OmniFocus.ofocus.lock. Delete that file and then launch OmniFocus. Does the error message still occur?

I was having this problem this morning, and after I threw that "lock" file away, the problem was resolved. My thanks to DannyG for starting this thread and to Lizard for helping me resolve it.