Directory Opus Blank

I've been using Opus for a couple of years and all of the sudden today, it is completely blank:

I can't do anything or access any of my bookmarks that are supposed to be on the left. There is no menu at top to change things either. Can you tell me how to fix this? This just started happening yesterday. I am on windows 11.

Please see here for how to get the toolbars back:

Out of interest, what anti-virus / anti-malware software do you use?