Further information: In DO, I can switch between various views (large/small icons, thumbnails, tiles) and the folder icons show up just fine. It is only the list, details, power views--which all use the same icon size--where icons are missing. As stated above, there are no missing icons in Windows Explorer.
It's indeed strange only some icons are missing... I cannot find any common denominator which would identify why only some icons, all of which are the same size, are missing.
Note that It is only the folder icon that exhibits this problem.
I just discovered this: If I move a group of folders, some with missing icons, some not missing folder icons, to another drive, then move them back again, all icons are "restored" and show as they should!
If all of the icons were not actually the same image, I'd suggest this problem is an issue concerning display resolution (1680 x 1050).
The problem is most likely an icon/overlay shell extension installed by something which is crashing when called by Opus. For some reason, several cloud storage apps have been doing this recently, at least some versions of them, but there are other types of app which may also be involved.
The ShellExView tool will let you see, and try disabling, the extensions your system has installed.
Please try running ShellExView, then sort its list by Type, and scroll down to the Icon Handler and Icon Overlay Handler entries. Right-click them and tell ShellExView to disable them.
Then, fully exit Opus (e.g. via File -> Exit Directory Opus; closing all the windows is not enough) and re-launch Opus to see if the problem is still there.
If that doesn't help, you can re-enable them in the same way. But if it does help, try re-enabling a few at a time until the problem comes back, narrowing it down until you find the one which seems to be triggering the problem.
I assuming (ah, don't ever assume anything) one of the icon handlers and/or icon overlay handlers which is not Microsoft-authored is the best place to start. I find entries from five other publishers including GP Software which I need to disable as you have outlined.
I will not get to this project quickly but will in due course and report back here what I find when I find it (which may be several days). Work continually interferes with what's interesting, dang it. One day I will have to find a way to enjoy life without the apparently necessary proceeds of my labors.
Based upon your directions I started out by disabling the icon handlers for DropBox. Although I don't know what impact that will have on DropBox yet, it immediately did "fix" the problem I was having. For a time, I got the correct icon with what looked like two question marks overlayed on the icon. I deleted iconcache.db, rebooted and the problem was totally gone. Thank you, Leo.
In passing let me mention two items of indispensable software:
[ul]Nirsoft Utilities: There is no problem in Windows, the cause of which cannot be determined and usually fixed, using these designed-to-the-purpose utilities.
Windows System Control Center ("WSCC"): It puts the Nirsoft Utilities and the Sysinternals Suite at your fingertips and keeps them updated.
[/ul]Both are absolutely free and there are no attached "hooks" to download other software or otherwise invade your computer.
Again, thank you Leo. You help keep Directory Opus awesome!