I am not a Mac person, and not at all familiar with the operating system. Are you saying that the DNG converter 10.3 will not even install on your system?
Dear Jim, Thank you for your comment. Yes, it´s not possible to install the DNG Converter 10.3 on my Mac. Today I talked to a colleague at work and after the discussion I believe I need to dig more into the Mac OS Version issue and the update status.
Just a side note. Your camera is actually supported in Lightroom 6.8 / 2015.8 so if you update to that version (or later) you should be able to import those files into Lightroom without converting to DNG first. You may have other reasons to use the DNG Converter, but I wanted to point that out.
Have a similar issue with Mac OS 10.13.4 (17E202) (High Sierra). I have installed the app several times and all I get i a blank screen when I open the app. About DNG Converter is blank... and no functionality seems to display. The apps screen just shows a blank screen with nothing - as i said - it is blank. Sometimes it will abend with a dump.
Does not matter how I open the app. Can open the app itself and get the above screen shot. Can click on a NEF file and select the DND Convert app to open the image and get the same screen shot as above.
Bottom line - it does not do anything.... i.e. work.
Just as a side note.... I can convert NEF to DNG via the Adobe Bridge import. I was trying to use this app for some IR Color NEF images.