For viewing .MSG files (e.g. from Outlook), if the viewer which comes with Outlook is not working well for you, there is an alternative which you can try here:
https://www.brandsict.nl/msgpreviewer_en.php
This works with both Directory Opus and File Explorer.
Note: Opus 12.19 or later is required, as we had to add some workarounds for a couple of issues.
There is this new Open Source multi-preview tool called QuickLook which is generally very convenient, especially in Windows Explorer with its limited capabilities. You simply select a file and press the Space bar, and the preview is displayed
This tool also pre-views Outlook MSG files. This is relatively spectacular, as this is the only tool existing (apart from the Brands ICT tool above) that can preview Outlook messages.
It's also all the more fortunate because Outlook's native preview has the annoying property of not responding until Outlook has connected to the mail server every time a message is to be pre-viewed. As a result, with the native preview of Outlook messages, it often takes many seconds for the message to be displayed.
Also, QuickLook is the only third party tool that can display Outlook messages in full rich text format, including inline images:
The Brands ICT plugin on the other hand shows only rather rudimentary plain text without formatting or inline images:
Therefore, it would be fantastic if there was a way to make the QuickLook Outlook preview work for Dopus as well, if that should be possible. It seems that these DLL files are responsible for the Outlook preview (in both EML and MSG format):
QuickLook.Plugin.MailViewer.zip (272.9 KB)
Thanks @Dopus Team for possibly considering this feature request.
David.P
So QuickLook isn’t a preview handler (doesn’t affect Explorer’s viewer pane), but instead opens its own window when you push space?
If they implement the preview handler API then their viewer will/should work in the viewer panes of both Opus and Explorer.
Hi David,
how to install the viewer, means the *.dll files in Dopus?
I already tried to copy them in *\VFSPlugins or in *\Viewers, but under SETTINGS -> Viewer -> Plugins or under SETTINGS -> Viewer -> Plugins -> AcriveX + Preview + Office + Web your plugin is not visible ...
Does your plugin actually support German "umlauts" (so "ä", "ü" etc)? - This is because BrandsICT Msg can not.
Thx.
Only Opus-specific plugins should go into those folders. Don't put random other DLLs in there. 
Yes this is how I understand it, and what it does.
Yes, umlauts and the like are fully supported in QuickLook.
The files attached above are only those DLLs that are responsible for the mail preview.
As Leo said, they probably won't work directly in Dopus. For those DLLs and the QuickLook Previewer to work, the whole download is needed (also works in portable mode).
David, I tested yout plugin via potable-install:
(+) = PLUS = layout and and german umlauts (so "ä", "ü" etc) are correctly rendered in the preview;
(-) = MINUS (till now) = does NOT support (unlike BrandsICT-Msg) MSG-files longer than 256 characters together with characters of the path (both DOPUS and BrandsICT-Msg support this).
It would be nice if your plugin could do this too. 
Thx. & Cheers
Thanks, I also have this use case occasionally. Please note however that Quick Look is not programmed by me, but by Paddy Xu.
Ask them to implement the preview handler API in that case. It's what any viewer on Windows should do as a minimum, really.
Done (and rejected for the time being, unfortunately)
Hi all,
What are the latest experiences with the Brands ICT MSG Previewer, possibly on Windows 11?
Does it still install and work without issues?
I need to ask IT to install it, so I want to be prepared for any potential issues.
I also use it in Voidtools Everything and in Windows Explorer, so I'd appreciate any experience anybody might have with this previewer also outside of Opus.
