The problem is probably external to Opus: We do not have a stream of people reporting the same problem, how Opus asks for icons has not changed in years, and Opus just asks the OS for the icons, and displays what it gets back.
If icons come back blank it has almost always turned out to be one of two things:
[ol][li]A shell extension -- often the DropBox one I already mentioned, or other cloud-storage extensions -- which, for whatever reason, crashes inside the Opus process but not others on your system. (But if you search, you'll find reports of them crashing inside Explorer as well. It just doesn't always affect every program on the system.)
Use ShellExView to disable the DropBox shell extensions. That usually fixes missing icons. Trying it will take only a few minutes; less time than writing a reply, so please give it a go. You just need to download the tool, run it, find the DropBox extensions in the list (and any other cloud-storage extensions), right-click, Disable, then reboot.
[/li]
[li]Sometimes the system icon cache for the Opus process gets corrupted. Running my Clear Icon Cache will clear the cache and fix the problem if that is it. You just have to download it, unzip it and double-click it, so it's very quick.[/li][/ol]
There's probably nothing that we can fix or debug on our side because the problem is almost certainly external to Opus, and the things above must be tried first to rule out the most likely possibilities.