Getting Access denied when trying to run \support\adprep>adprep.exe /forestprep /forest domain name with admin rights.

Question

I am upgrading my WS 2016 standard to WS 2019 standard, Everything was going fine until it asks me "Active Directory on this domain controller does not contain Windows Server 2019 ADPREP /FORESTPREP updates. See https://go.microsoft.com/fwlink/?LinkId=113955." So I looked up what to do and I found I need to run the \support\adprep>adprep.exe /forestprep /forest <domainname> command line prompt. I run the command line prompt under Administrator and I get Access is denied. I've checked everything and I am the admin on the folder and drive and entire server. Just don't understand why I still get this error.

Answer 1

Hi @Michael Woodward

Your admin account needs to be a member of the Enterprise Admins, Schema Admin and Domain Admins groups to complete the ADPrep. You will also need to run the command on the Domain Controller that is holding the schema master FMSO role.

If your account is a member of all these groups, please post the full error message that you are receiving.

Gary.

Answer 2

Hello @Michael Woodward

if you didn`t try this yet, try to disable any third-party product and re-run the adprep command.

If you have other issues with adprep, you may refer the logs from this path “C:\Windows\Debug\adprep\”.

Sometimes even logged on as a member of the Domain Admins group, the Enterprise Admins group, and the Schema Admins group, you STILL will be required to use "Run as Admin" for a command prompt. Don`t ask me why...

Hope this helps with your query!

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Answer 3

Good Afternoon.

Thank you for your response.

I am running admin account as a member of the Enterprise Admins, Schema Admin and Domain Admins.
I am also running the command on the Domain Controller that is holding the schema master FMSO role.

No third party products to disable.

I do not see the “C:\Windows\Debug\adprep\” folder.

I am also running the command prompt as Administrator.

Is there anything I should be looking at. Thank you for your help.

MW

Answer 4

Hello Gary
Let me know if you see this.

Thanks
MW

Answer 5

Hi @Michael Woodward

From the screenshot, it looks like the error is happening when trying to access the adprep program, rather than an AD access error. I would try changing to the support\ADPrep directory and run the command directly from the directory and see if that makes any difference.

Gary.