I don't think anybody has mentioned Opus 9 until now in the thread. People are talking about Explorer vs Opus, as far as I can tell.
That's also strange since the way Opus copies files didn't change between Opus 9 and Opus 10. A lot of other things have changed, but not that.
Maybe one of those 9->10 changes has triggered a problem on your setup. (e.g. Some graphics/motherboard drivers are really sensitive to the way progress dialogs are updated, in my experience. It can be quite random things like that. Or it can be more obvious things like antivirus or firewall software that works using signatures and sees two versions of Opus (or whatever) as different, and treats them differently.)
If that is due to high CPU usage, Process Explorer may be able to indicate what is using the CPU.
- Run Process Explorer as admin.
- Find the process using lots of CPU (it may be dopus.exe or it could be "System" if the problem is happening within the network filesystem driver; it could also be a firewall/anti-virus/etc. process).
- Open that process's properties, then go to the Threads tab.
- Sort the threads by CPU. There's probably one thread responsible for almost all of it. Select that thread.
- Click the Stack button and see which components are listed. The non-Windows ones nearest the top are usually responsible, and if they are not Opus components then you may have your culprit.
(See W0lfdale's suggestion in an old thread for an alternative description of what to do, with screenshot. That's linked from the general troubleshooting FAQ which may have other things worth trying.)
Have you reported that problem anywhere? It can't be explained/fixed unless it's reported, and it doesn't sound related to this thread.