In windows 10 ,I can ́t to establish email client as default, ir ́s give me an error: “Either there is no default mail client or the current mail client cannot fulfill the messaging request…”
That is a problem within your copy of Windows 10 - something somehow is blocking the change to make eM Client the default. I had no trouble making eM Client the default application in my copy of Windows 10 Pro.
Luis, I found a link that might be useful for you in solving your problem:
Look here, as I have described it.