Questions about viewers

  1. I'm trying to see if I can view ocuments using a viewer so that if, say, I press F7 the document would open in a new window rather than in a viewer pane. Alternatively, is there a way to maximise the viewer pane? Currently I use a lister with a folder tree and two panes.

  2. Trying to view pdf files crashes DOPUS (

  3. The Preferences settings show a plugin called Multiview. When I try to configure this plugin, there is a message that the viewer dllls could not be located. Where should the viewer dlls be in my running Windows 7 Pro 64bit?

(Please ask one question per thread.)

  1. Settings -> Customize Toolbars... -> Commands, then drag File Commands -> Show to your toolbar. (Alternatively, just make a button/hotkey/etc. which runs the Show command.)

  2. Which PDF viewer(s) do you have installed? Do you get the same crash using the viewer in Windows Explorer? (If not, does it show the file?)

  3. On 64-bit Windows, you're best to ignore the MultiView plugin. If you want those viewers, they come with Quick View Plus 11 (or above) in the form of Preview Handlers which will work in Opus automatically (via the ActiveX + Office + Web + Preview plugin).

  1. Thank you for your reply. It's very nice now to have the viewer open outside the panels.

  2. The PDF viewer that I use is called PDF Complete and was preinstalled in my PC when I bought it. There are no crashes or any other problems when I use Windows Explorer. In DOPUS, after applying the solution to my first question i.e. adding the button to the toolbar, opening a PDF file gives the following error before DOPUS crashes:

docsvw32.exe - System Error

The program can't start because PDFNetC.dll is missing from your computer. Try reinstalling the program to fix this problem.


  1. Thank you for the advice aboout the Multiview plugin.

docsvw32.exe - System Error

The program can't start because PDFNetC.dll is missing from your computer. Try reinstalling the program to fix this problem.


My guess is that PDF Complete is trying to load PDFNetC.dll via the program's current directory, instead of either placing the DLL somewhere in the sytem path or loading the DLL via its full-path.

Programs which do this, especially file viewers, are a security risk. (It's also not a safe thing to do within multi-threaded programs -- i.e. almost anything these days -- because the current dir is process-wide and another thread may change it or may be depending on it not being changed at the same time.)

Because of those issues, docsvw32.exe removes the current directory from the DLL search path when it starts. (dopus.exe does the same.) This plugs the security hole but will break the handful of 3rd party components which actually depend on it. (Anything which depends on it should really be fixed.)

This is just a guess, though. I could be wrong.

If you want test my theory:

[ul][li] Open Regedit.exe[/li]
[li] Go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager[/li]
[li] See if there is a existing CWDIllegalInDllSearch value.
[ul][li]If there is, make a note of its current value.[/li]
[li]If there isn't, create one by right-clicking the right-hand side, New -> DWORD (32-bit) value.[/li][/ul][/li]
[li]Set the value to ffffffff (hexadecimal). (This will force all applications to be as strict as docsvw32.exe is.)[/li]
[li]Try to view a PDF in Windows Explorer and see if it now also has the same error.[/li]
[li]Restore the registry value to what it used to be and reboot again to return to normal (assuming you don't want to keep the strict behaviour).[/li][/ul]

CWDIllegalInDllSearch is documented here:

Thank you for the information; it's a little scary!

I uninstalled PDFComplete, downloaded Sumatra PDF, which is a freeware program requiring no installation, made Sumatra the default pdf reader and tested it with DOPUS. Pressing F7 opens pdf files in a panel, but I'm asked if I want to open or download(!) a file in a temporary directory or cancel the operation. I have the option to stop showing this dialog, but I have not yet done so.

If I press the viewer button on the DOPUS toolbar, the same dialog comes up, and when I press "open" the pdf file is opened in Sumatra. However, after I close the pdf file, there is a viewer window open, stating that "navigation to the webpage was cancelled".

Further to the previous posting. I installed Foxit Reader and the DOPUS viewer (toolbar button) as well as the viewer panel (F7 key) work smoothly.