Windows 8 Microsoft Account: The login screen always shows Other User after the reboot

I got my HP Windows 8 (Consumer) laptop recently and I used Microsoft account to set up this machine for my wife. “Microsoft account" is the new name for what used to be called a "Windows LiveID."

I also applied latest Windows 8 update.  After that, I added a user via my Microsoft account with admin right. I could not believe my wife and I  got truncatedusername_000 in the user profile as follows: 

After 1 day, my wife didn’t like Windows 8 and said she will not use it any more. Therefore,  I deleted her account.

I added a new language (Chinese Traditional), changed system locale to Chinese and it caused the reboot. After that, I could not believe I saw the other user login screen. When I clicked ok, it showed the login name – my wife Microsoft account (sun42_000), which was deleted already.

I also noticed: After I changed the system locale back to the US and still used my account in Windows 8, the latest Windows update caused the reboot and the login screen still showed the deleted Microsoft account (sun42_000)

This is a very basic scenario (BVT). I can’t believe Microsoft Windows Team shipped Windows 8 to customers. 

After that, I don’t like Windows 8 and I successfully upgraded Windows 8 to Windows 7. (Successfully upgrade Windows 8 to Windows 7 on HP Pavilion G7-2240US and fix the issue of Windows cannot be installed on this disk. The selected disk is of the GPT partition style)