Windows 10 in-place upgrade and Active Setup

So we take this:

Active Setup is a mechanism for executing commands once per user early during login. Active Setup is used by some operating system components like Internet Explorer to set up an initial configuration for new users logging on for the first time. Active Setup is also used in some corporations’ software distribution systems to create an initial customized user environment.
(Wikipedia)

Add this

It must be pointed out that the “Active Setup” mechanism has never been publicly documented and Microsoft will not necessarily support any use of Active Setup by any component that doesn’t ship within the Windows product.  There are lots of undocumented mechanisms.  In general, people representing Microsoft should not recommend their use — at least not without plenty of caveats.  My $0.02.
(Aaron Margosis)

For result:

Microsoft does not support the migration of non-Microsoft Active Setup registry entries.  If you want to in-place upgrade to Windows 10 in your enterprise, you have to migrate the keys manually.