We are starting to test Windows 10 in our enterprise. We have roaming users and there are known issues around profile management.

From AppSense,

In fact, if you look into profile version compatibility (you should, it’s a fascinating read) you’ll see that profiles are only ever compatible between one desktop and one server. So, Windows 7 profiles are only compatible with Windows Server 2008 R2. Windows 8 is only compatible with Windows Server 2012. And, Windows 8.1 is only compatible with Windows Server 2012 R2. Microsoft describes this in their knowledge base article 2887239.

So how do you keep roaming profiles separate for these incompatible platforms? And how will Windows 10 change things?

The answer is to use the same approach you used when you migrated from XP to Windows 7 – use a new profile version for each OS.

This is done by installing the Microsoft hotfix, which causes Windows 8 to mark user profiles as v3. You can activate this functionality with the following registry key

HKEY_LOCAL_MACHINE\System\CurrentControlset\Services\ProfSvc\Parameters\UseProfilePathExtensionVersion (DWORD=1]

The same is true for Windows 10 (v5) and the same Microsoft fix can be used.