windows live mail mailto: hyperlink

Until yesterday, I could create a new email with a mailto: hyperlink by selecting some text, going to the hyperlink dialogue box, entering 'mailto:' plus an email address in the Web address box and clicking Insert. The selected text was then underlined, coloured as a hyperlink, and when the cursor was hovered over the text, the mailto: plus address could be seen. Since yesterday morning I have not been able to do this. There is no error message, but the text is not underlined, coloured or clickable. I can create hyperlinks to web addresses OK, just not mailto: hyperlinks. I have not changed any settings on my pc, but there was a big update from Microsoft yesterday morning and I think this has caused the problem. I rely on being able to create mailto: hyperlinks in my emails. Please advise. I am running Windows 10 and using Windows Live Mail 2012 as my mail handler. Thank you,