Swarm Failed to kick off (File being used by another process)

Jarek the problem has somewhat sorted itself out now. When i upgraded to 4.5, i created a new level and it works now but when i try and build lighting in the old level it still happens. the problem was with swarm it was something about that specific “Job” the level im using now has a different file but when it tries to access that other file for the old level it still happens. so its some sort of bug in swarm