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Cannot raise forest / domain functional level to 2012r2 if members servers are 2008r2

    Question

  • Hello experts, hope you can help me on this one, it's driving me mad!

    Scenario: I have a small network with just 1 DC (2008 r2) and several member servers (2008 r2). There is just ONE DC. I have to move to AD 2012 r2, therefore I installed a 2012 r2 datacenter server, added to the domain and promoted to DC. After that, I followed all the necessary steps to remove the old DC and now have only one 2012 r2 DC.

    When I try to raise the forest or domain functional level, the system tells me I cannot go past 2008 r2. After too many tries to identify rogue data with ADSI edit, I decided to setup a test environment and the results are surprising.

    I created a brand new 2012 r2 DC, dcpromo to a brand new domain, and installed a 2012 r2 member server: I can raise the forest and domain level to 2012 r2.

    Then I created another brand new 2012 r2 DC, dcpromo to a brand new domain, and installed a 2012 member server: I can ONLY raise the forest and domain level to 2012.

    Then I created another brand new 2012 r2 DC, dcpromo to a brand new domain, and installed a 2008 r2 member server: I can ONLY raise the forest and domain level to 2008 r2.

    How is it even possible, or what am I doing wrong? It is my understanding that ONLY DCs must be 2012 r2 to raise the forest/domain to 2012 r2... not the member servers!

    Finally, I tried to run the Set-ADForestMode and Set-ADDomainMode commands: after that, (Get-ADForest).ForestMode and (Get-ADForest).DomainMode show the forest and domain as 2012 r2, but if I connect to AD Domains and Trusts, I receive this error: 'You cannot raise the forest functional level. Either the forest includes AD DCs that are not running the appropriate version of Windows, or one or more domains are still at Windows 2000 mixed functional level'.

    I am not sure I can post pictures here, but please believe me when I say that member servers are really member servers, not additional DCs.

    Your help is highly appreciated.

    regards,

    straniero75




    • Edited by straniero75 Sunday, October 22, 2017 10:02 AM
    Sunday, October 22, 2017 9:18 AM

All replies

  • thanks Dave.

    as I mentioned, I have the issue in a test environment made of a brand new DC and a brand new member server, therefore there are no old servers.

    thanks

    straniero75

    Sunday, October 22, 2017 1:09 PM
  • Hi,
    It is a strange problem for me, could you please post us the step-by-step actions when you promote the DC? And did you use GUI wizard to promote the DC?
    Best regards,
    Wendy

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    Wednesday, October 25, 2017 8:05 AM
    Moderator
  • hello Wendy,

    I created a new empty test domain and promoted the 2012 r2 core using this command:

    dcpromo /adv /ReplicaOrNewDomain=domain /InstallDNS=yes /NewDomain=forest /NewDomainDNSName=DOMAINDNS.LOCAL /DomainNetBiosName=DOMAIN /SiteName=SITE /RebootOnCompletion=yes /SafeModeAdminPassword=PASSWORD /ForestLevel=6 /DomainLevel=6

    (I know it's deprecated, but still working).

    To add any server to the domain, I just use the graphical procedure (right click computer, properties, change settings, change, type in domain name...) like I would with any other client.

    after that... if the member servers are not r2, I cannot raise the functional level to r2. If, however, I just add one r2 member server, I can raise the functional level to 2012 r2.

    puzzling :(

    If needed I can post pictures?

    thanks for your help

    regards

    Michele


    • Edited by straniero75 Wednesday, October 25, 2017 11:13 AM
    Wednesday, October 25, 2017 8:58 AM
  • hello and sorry for the bump. but does anyone have any idea?

    thanks,

    straniero

    Thursday, November 02, 2017 11:24 AM
  • what is your current functional level ?
    Thursday, November 02, 2017 4:37 PM
  • sometimes I wonder...

    IF I install a brand new 2012 r2 DC and a 2012 r2 member server, I can raise the functional level to 2012 r2.

    IF I install a brand new 2012 r2 DC and a 2012 member server, I can raise the functional level to 2012.

    IF I install a brand new 2012 r2 DC and a 2008 r2 member server, I can raise the functional level to 2008 r2.

    There is really no 'current' level because every time I do the testing (see the 3 examples above) I create a brand new test domain).

    thanks

    straniero



    • Edited by straniero75 Friday, November 03, 2017 5:02 PM
    Friday, November 03, 2017 2:50 PM
  • Hi straniero,
    When you promote the first DC, are you able to raise the function level into the correct one before you add member server?
    Best regards, 
    Wendy

    Please remember to mark the replies as answers if they help.
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    Monday, November 06, 2017 1:30 AM
    Moderator
  • Functional Levels are only applicable to the Operating Systems of the Domain Controllers. If you wan't the raise the Forect Functional Level to W2012R2, all the Domain Controllers in the environment must be W2012R2 or Later.
    As you have W2008R2 as a Domain Controller you won't be able to raise the functional level; however you still will be able to bring W2012R2 as a Domain Controller (Additional domain Controller).

    After bringing a new W2012R2 as Domain Controller; you need to remove ADDS from W2008R2 and then you will be able to raise the functional level to W2012R2

    Hope this helps...



    Dev T

    Monday, November 06, 2017 5:04 AM
  • 

    Hi,

    I am checking how the issue is going, if you still have any questions, please feel free to contact us.

    And if the replies as above are helpful, we would appreciate you to mark them as answers, and if you resolve it using your own solution, please share your experience and solution here. It will be greatly helpful to others who have the same question.

    Appreciate for your feedback.

    Best regards,

    Wendy


    Please remember to mark the replies as answers if they help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Friday, November 10, 2017 8:31 AM
    Moderator