Windows 10: You've been signed in with a temporary profile

Hi,

Thank you for being a part of Windows 10 Technical Preview.

Are you connected to domain?

If you have been connected to domain, then it would be better suited in TechNet community.
https://social.technet.microsoft.com/Forums/en-US/home?category=WinPreview2014

If you are not connected to domain, then I would suggest you to try the following steps.

Enable Built Admin account.

a) Press Windows and x key together on your desktop screen.
b) Click on Command Prompt (admin).
c) Type: net user administrator /active: yes

Note: Please follow the same steps and type net user administrator /active: no to disable admin account after the troubleshooting is done

After enabling Built-in admin, please try with the steps below:

System file check is a utility built into the Operating System that will check for system file corruption The sfc /scannow command (System File Check) scans the integrity of all protected operating system files and replaces incorrect, corrupted, changed, or damaged versions with the correct versions where possible.

Use the System File Checker tool to repair missing or corrupted system files
https://support.microsoft.com/en-us/kb/929833

Let us know the update after you try the above steps.