And if I'm not using Acrobat DC but open-source PDF reader? (Foxit). I'm having inconsistent results with being able to see images of PDF documents in the pane. Visible, then not. However, WinExplorer shows PDF images of same document in its pane. Thanks.
If the images are external to the PDF (not something I’ve ever seen, but perhaps it’s possible) then that could be the reason, as Opus will ask viewers to open temporary copies of PDFs to avoid the viewers locking the files from being moved/renamed/deleted.
Other than that, what the different PDF viewers do is entirely up to the viewers themselves. You should ask the people who make the viewer if you’re seeing it not display some images.
(AFAIK, FoxIt isn’t open source, although that has no bearing on how it works anyway.)
I see from Task Manager that AcroRd32.exe *32 is running ... although I don't have Acrobat DC open. It's not been open in my current boot Yet AcroRd32.exe 832 is using 8% of my large CPU. I have DOPUS pointing to two PDFs but the time cursor just spins around. It would seem to me (end-user/not geek) that Adobe is involved here even though DOPUS labels these PDFs as "Foxit PDF Documents." Suggestions appreciated.
We’re not able to fix issues with Adobe Reader if it’s misbehaving, other than to suggest reinstalling it or switching to other PDF software, as Adobe Reader isn’t our product.
...just uninstall AcroReader (when Foxit is used anyway)?
Adobe doesn't play nice...it's known to strip out MS system scripts behind itself when uninstalled---including the script that allows WinExplorer to show PDF images in the preview pane. If Acrobat is not installed, Explorer could not preview PDFs. I followed all suggestions in different forums. I'm at the point of reinstalling Windows although my installation is only a few months old. Or moving D-Opus to an out-of-the-box machine.
If one PDF viewer breaks another you can usually fix it by reinstalling the one you want to use. (Not sure if that applies to the Microsoft one, as it's part of Windows. There may be another way to repair it.)
Using right-click > Open With > Choose Default Program on a PDF file also often works to reset the viewer.
In Opus you can also change which PDF viewer will be used by going to Preferences / Viewers / Plugins and configuring the ActiveX + Preview + Office + Web plugin (which acts as a metaplugin between Opus and things like PDF viewers).