I use a lightweight PDF viewer called PDF-Xchange (http://www.tracker-software.com), because it can generate PDF thumbnails without the bloated Adobe Reader. I see the PDF thumbnails in Win Explorer, but DOpus gives me the PDF icon. I thought that if Win Explorer can generate thumbnails, DOpus can do this, too? Is there a switch in DOpus which switches off thumbnails for some extensions?
It's probably using a new thumbnail method that was introduced in Windows 7 that Opus doesn't support yet. Support for this will be added in Opus 10.
So when's Opus 10 coming out? I need to buy a champagne bottle to mark the reintroduction of PDF thumbnails to my PC. I haven't seen them since 2006, which was the last time I was willing to install the 250 MB Adobe Reader. You'd think PDF thumbnails wouldn't be hard in 2011, but noooo... Adobe Reader needs 250 MB of space (probably 0.5 GB by now), Foxit has been promising thumbnails since 2006 with zero follow-up, PDF-XChange does thumbnails, but not in DOPus... It's a life of frustration.