I also found just the first name is the actual username. This is important for certain third-party applications that borrow the login credentials from Windows.
The Windows 8.1 environment NEVER asks for your username. When it shows the 'username' it is in an email address form. This may not be the actual username (as the previous post shows, it may be just the first name portion), which makes figuring out what the heck these third-party applications are looking for... entertaining. I eventually guessed my own, since I had set up my Windows copy only a few weeks earlier, but I am running into this problem at several places. Thanks for the solution.
This reminds me of the obnoxious 'hide extensions for known file types' setting that invited all sorts of mislabeled viruses to get clicked on, which is annoying, useless, and potentially dangerous.
There I just see my old local username I had before. Seems to be connected to that Microsoft Account now... – FiveO – 2012-10-22T08:57:50.540
That sounds right to me. In my case it was a new PC so I didn't have an old account, but after I signed in with my Microsoft account I wound up with a local account of just my first name. – Mark Allen – 2012-10-22T18:30:57.657
I’m relaying a comment from an anonymous user who says, “In my case, the name is the first five letters of the login name followed by series of digits; e.g.,
thisisjustasample
becamethisi_000
.” – Scott – 2013-03-12T23:19:45.120