I tried several browsers meanwhile but experience the same issue with each of the plugins.
File associations work fine (url, http, https), after answering the "how do you want to open this file dialog". (BTW, is there a way to avoid this popup and just go ahead and use the program associated?)
Here is my problem now. There are some programs (for example Ransomeware File Decryptor, Virustotal Uploader) which also try to open a browser to navigate to a Website.
They obviously try to invoke the browser in a different way, As for example clicking the link in the Ransomeware tool does not seem to do anything. The uploader is also not able to open the browser to show the result website.
I played with the default programs settings a bit, but could not resolve this. I know this worked in the past, but am unsure what step made this fail. I am running with German Win10 Source, no admin login.
Thanks for your help...