Why does IE11 (or Windows 10) change my user name when logging into SSL sites?

[Windows Central Question]

Why does IE11 (or Windows 10) change my user name when logging into SSL sites

Since the latest major Windows 10 update (fall 2015), Internet Explorer has been refusing to log me into SSL-protected (https websites without me having to alter the recorded user name.

Windows changes my user name to MicrosoftAccount\my.email@address.com, even though the original user name was a short plaintext one. Windows does remember the correct password, so all I have to do is change the user name back to the correct one.

Next time, I log into the site, however, the user name is back to the MicrosoftAccount one.

Any idea how to fix this?

 

[orlbuckeye]

Are you running delete browsing history when you exit IE? That could do it as you password is cached and if you delete the history on exit in the setting it would do that.