The internet is full of complains that Admin Pack for Windows 2003 cannot be installed due to protected Windows files. I guess that this can happen for various reasons, but I have found a solution for at least one of the cases – when the server where the installation of Windows 2003 Admin Pack fails is virtualized.
So, we have two servers – Windows 2003 Server with Active Directory installed as Domain Controller (server #1) and VM with Windows 2003 Server that is a member of this domain (server #2). The need – administer DNS and DHCP settings of AD remotely, but corresponding MMC snap-ins are not available by default on non-DC machines. The correct way is to install ADMINPACK.MSI, available from Windows 2003 installation CD-ROM or from Microsoft Download Center. (Of course, you can always open an RDP session to a DC – but this does not address the real need.)
However, the installation suddenly shows a message “The Windows Installer service cannot update one or more protected windows files” and rolls back everything that was already installed. The Event Viewer reveals error numbers (“Error 1933. … SPF Error: 1223.”) and the list of protected files – but this does not really help. So, what can we do about that?
In fact, the solution is really simple. Running the same installation via the console RDP session (or in the vSphere console) reveals the real cause for the failure – the Admin Pack install needs Windows 2003 installation CD-ROM, but for some reason does not tell that on non-console sessions. After the requested CD is provided (for VMs, this can be done by mounting the CD image in vSphere or via DaemonTools), the installation was able to complete successfully.