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Server 2008 domain to Server 2012 R2


I want to upgrade the Server 2008 domain controller to Server 2012 R2. (Reason we don't go for Server 2016 or 2019, we have only server 2012 r2 licneses)

I have already installed a Server 2012 R2 server and added to the domain.

If I don't run forestprep and domainprep, would that be a problem?
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AlexA lack of information provides a lack of a decent solution.


On 2012 I believe it does this when you install the AD role on the server.

Realistically, going to 2016 would be preferable purely because 2019 has no additional functionality over the 2016 DFL and FFL.

Also, 2012 doesn't fully support windows 10, it's a bit of a pain really.

Principal Support Engineer
If I don't run forestprep and domainprep, would that be a problem?

This is not a problem; these schema extensions are applied automatically when the 2012 R2 domain controller is promoted. Simply promote it, make sure AD and SYSVOL replication are both successful, and you're good to go. (You might be surprised how often people forget about SYSVOL. Then they retire their old DCs and everything goes haywire.)

At some point after you retire the 2008 domain controller, you should raise the domain functional level and forest functional level to 2012 R2. You may also need to migrate SYSVOL from FRS to DFSR, depending on the functional level that was in place when the domain was created.