For the last 10 years I have used a snippet of JavaScript in web pages to encode clients’ email addresses. These worked fine on all our websites until a recent Windows 10 Update.
People using Windows XP and Windows 7 have no problems with the live links.

Now our clients’ are complaining that the email links are only live when people access their websites using Edge, Internet Explorer 8 through 11, and Safari for Windows. These people are all using Windows 10. If they try to access the websites using Firefox, Opera or Chrome they get an error message as follows:

wlmail.exe - System Error
The program can’t start because WLDCore.dll is missing from your computer. Try reinstalling the program to fix this problem.

The file WLDCore.dll is present and Windows Live Mail works fine for sending and receiving emails so the error message is misleading.

Any help to solve this irritating mystery would be most welcome.