There is most likely a shortcut in there that points to something which takes a long time to resolve, combine with turning on the option to sort shortcuts to folders like folders. Shortcuts that point to unreachable network servers are often the cause of that.
It's also possible something has installed a shell extension which is going wrong.
The best thing to do first is to narrow down which file (or type of file) is causing the delay.
You can also send us process snapshots taken while the delay is happening, which we can analyse to see where the wait is, and whether it's in Opus itself or another component, and then fix it or suggest workarounds as appropriate.
More detail in the FAQs: