Unregistered file types (extensions) --> not bound to viewer

Hi there!

I did not find any similar topic and solution in this group, so here is my (little) problem:
I checked the option under preferences --> Double-Click --> Files --> "Open unregistered file types..." and left the box emty or pointed to my preferred editor (notepad2). In either case, files with no extension (fu) or with unknown ones (fu.bar) are not opened in notepad, the default WindowsXP "Open with" dialog shows up instead.
Interestingly, Windows Explorer does the job nicely, after I added
to the registry.

Can anyone please comment on this?

Thank you in advance,


Opus may check that the files appear to contain (mainly) text before sending them to the configured text editor. Try it with a small text file with just "test" inside if or similar and it should work. (Works for me with a file called "fu.bar".)

If that works but the other files don't, are there any non-printable characters in the files you're trying to open? They may be causing Opus to think it's a binary file rather than a text file.

Hi Nudel,

this one works. But IMHO it is not more than an testing scenario...
You can try to open %system%\drivers\etc\hosts (nothing more but text) for example... DO will fail trying. DO is an fantastic piece of software, but in that case its some sort of overkill (at least in my eyes) :wink:
Can DO just pass the file to the default windows handler in future versions?
One more comment: Windows Explorer shows the default "Open" entry, I added to the registry as posted above (actually, there are two "Open" functions: the first one directly opens the file (my "reg-hack"), the second one just shows the regular WindowsXP "Open with" dialog-box). DO lists neither of the two, exchanging the second one by "Open With". For your information, my sys is german and I did not install the german language pack...

Thank you for another hint,


Double-clicking the Hosts file opens it in my configured text editor here. :slight_smile:

Except when overridden, Opus does call the windows handler (ShellExecute) to launch/open things you double-click.

With the hidden context menu items, do you see them all if you hold shift when right-clicking the file?

Lucky one :slight_smile:

No. Pressing while right-klicking does not do a thing (I did not activate Preferences --> Miscellaneous --> Windows Integration --> Hide Windows items at any time)...

[quote="nudel"]Except when overridden, Opus does call the windows handler (ShellExecute) to launch/open things you double-click.

Strange enough, since deaktivating Preferences --> Double-Click --> Files --> "Open unregistered file types..." stops DO from opening these files at all (popping out "Open with" dialog). Still, WE opens them allways...

Maybe Opus just doesn't fall back on the "Unknown" filetype. Not sure how it works, to be honest.

BTW, You might need to put quotes around the %1 to avoid problems with spaces in the file path, although it won't make any difference to the main problem.

Also, in the Opus file types editor there is an item at the top called "Unknown file types" which you can set to use Notepad on the Open the double-click event. That should get you what you want.

Thank you for that one :slight_smile:

:slight_smile: I have never looked into this configuration dialog, it works - thank's a lot :slight_smile:

Excellent. :slight_smile: