I have been using Opus for many years now but have always had this issue.
I have browsed through this forum many times and tried all possible solutions, but the problem persists.
90% of the time when I load Opus, thumbnails for all types of files and folders takes a long time to load. Even if i go back to a folder where the thumbnails were previously loaded they disappear and I have to wait for them to load again. Sometimes rebooting my PC solves the problem, but not always.
It just seems to slow the whole of Opus down, even if I try to open the Preferences dialog box while it is loading thumbnails, nothing happens, but it will pop up a few minutes later.
However, it only happens on my home PC (and my previous home PC). On my work PC it has never been a problem. I have been through the entire Preferences section on both PC's to make sure all settings match. The only difference between the two that I can think of is that my home PC has Norton installed, whereas work PC uses Avast. I read somewhere here that Norton can slow down thumbnail loading so I have blocked it from scanning the Opus thumbnail folder as suggested but this didn't make any difference. I also tried turning off icon handlers (?) in shellextview and this worked for a while on my previous home PC but not on my current one (If i turn off handlers for Windows it causes problems).
I'm really at a loss here as I've tried everything but nothing seems to solve the problem.
Both PC's use Windows 10.
ps. apart from this problem though I absolutely love Opus