If you search your C:\ drive for stobject.dll, which folder(s) is it located in?
The crash mentioned stobject.dll_unloaded, which indicates that a DLL (probably a shell extension from another program) has created a window or installed a callback/hook of some kind, and then not prevented Opus from later unloading the DLL. The DLL's code is then called, but is no longer in memory, so it crashes.
Opus may unload DLLs it no longer needs at different times to other programs, which might expose a bug in the DLL that other programs happen to avoid triggering.
Oh, stobject.dll is part of Windows itself, and seems to be loaded and then unloaded normally when using the Set as desktop wallpaper command for me.
I just remembered that there is a confirmed bug in Windows 7 where invoking Set As Desktop Wallpaper from any app (doesn't have to be Opus) other than Explorer can result in a crash. We reported this bug and got a confirmation from Microsoft back in 2009 but (of course!) they have still not bothered to fix it:
However, newer versions of Opus should automatically intercept that command on Opus's own file context menus and replace it with Opus's own set-wallpaper code, and that still seems to work for me in 10.0.5.1-beta.
Where are you invoking the command from? Is it when right-clicking a file within a normal folder (not a special/virtual folder) within an Opus lister, or from somewhere else within Opus (e.g. a File->Open dialog)?
Where are you invoking the command from? Is it when right-clicking a file within a normal folder (not a special/virtual folder) within an Opus lister, or from somewhere else within Opus (e.g. a File->Open dialog)?
Works correctly from a normal folder "C:\Users\BarKeep\Documents\Themes\Wallpaper", but crashes from Libraries "lib://Documents/Themes/Wallpaper"
The commands are in the default toolbar, in the Tools menu.
You can put the same commands in the right-click context menu if you want, or just use the Tools menu as-is.
If you need more help with this, please start a new thread as this thread is about an old crash, when using the Windows context menu item rather than the Opus ones, which has long since been fixed.