That could be a lot of things, inside or outside of Opus. We aren't aware of anything that would cause that in Opus 12.14, but we've seen things do it in the past. (The ones we've seen within Opus itself have all been dealt with, but it could be a shell extension or antivirus doing it, perhaps.)
Which version of Opus are you seeing that with?
Have you tried the FAQ about this type of issue? Crash, exit or high CPU when viewing certain directories