High CPU usage (and other issues) when folder tree locked

Another thing to note: That just shows that the thread using the CPU was started by Opus. Most threads in the process will be, of course.

You need to select that thread and click the Stack button to see which DLL is currently executing, which may indicate where the problem is. (How to find components causing high CPU usage has instructions.)

But the process snapshots will contain the same information, so we can do that investigation for you as well.