Missing volume name and letter in tree

There is an issue with Kaspersky messing up change notifications unless you whitelist the process:

That affects other software, not just Opus, but it seems to treat different applications differently, and not all apps depend on the change notification API that Kaspersky sometimes breaks. So it doesn't cause problems with all software, but it has been known to break that Windows API, which could be involved in what you're seeing happen to that drive.