Windows 7 and Windows 8 both use version 2 profiles. However, they are incompatible. Interoperability is not supported when user profiles roam between Windows 7-based computers and Windows 8-based computers.

If you have Windows 7-based computers and Windows 8-based computers in a network environment and the
User accounts are configured to use roaming profiles when users log on to the computers, when you use a user account that has a Windows 7 profile to log on to a Windows 8-based computer for the first time, the user profile is updated to the new Windows 8 format.

Now when you try to use the same user account to log on to a Windows 7-based computer, the user profile format is no longer compatible with the Windows 7-based computer.

To resolve this issue, download and apply hotfix from KB2887239.