PRB: MDAC 2.6/2.7 Roll Back Installation or Get Error on Install

When you install Microsoft Data Access Components (MDAC) version 2.6 or later on a computer that is running Microsoft Windows 2000 or Microsoft Windows XP, either the installation program completes but does not actually install MDAC, or it displays a message box that says it is rolling back to the previous installation.

This error can occur during the Component Update part (step 1) of the Microsoft Visual Studio .NET installation, or during the MDAC part of the Microsoft SQL Server 2000 installation. You receive the following error message: When you examine the Dasetup.log file found in the C:\Winnt directory, you see that either the installation process just stopped, or that Odbcconf.exe failed. For example, you may see the following information in the logs: SQL Server 2000 setup may fail with the following error message: The Sqlstp.log file located in your \Windows or \WinNT directory may end with similar messages:

The "Unspecified error" message can occur if there is an older version of Odbcconf.dll on the computer. There is also a known problem with the MDAC installer where it fails during the middle of an installation. System file protection rolls back Odbcconf.dll in the middle of the MDAC installation. In the system event log, you see that system file protection occurred, and an event occurs with information that looks similar to the following:

The following two methods have been successful:

• Method 1: Look for older Odbcconf.dll files on the system, rename them, and then reinstall MDAC.
• Method 2: If the Odbcconf.dll file is not the problem, download and unzip the Unmgrt.exe file that is provided in the "More Information" section and then do the following:
  1. Put the Unmigrt.cmd and Unmigrt.rsp files in a folder on the computer that has the problem.
  2. Copy the Mdac_typ.exe file for the version of MDAC that you tried to install to the same folder. If you are seeing the failure when you run the installations for SQL Server 2000 or Visual Studio .NET, download the latest Mdac_typ.exe files from the following Microsoft Developer Network (MSDN) Web site:
     http://msdn.microsoft.com/en-us/data/aa937729.aspx
     The following list shows which version of Mdac_typ.exe you will use based on where you see the failure:

     Error Installing	Install
     Visual Studio .NET	MDAC 2.7
     SQL Server 2000	MDAC 2.6
     SQL Server 2000 SP1	MDAC 2.6 SP1
     SQL Server 2000 SP2	MDAC 2.6 SP2

     
     
  3. Run Unmigrt.cmd.
  4. Run the MDAC installation again. You should see that the MDAC setup is successful the next time that you try to install.

Important Use Unmgrt.exe only after you receive the error message that is described in this article. Do not use this program unless you have encountered a failed installation. If you have any earlier version of MDAC installed on the computer, running Unmgrt.exe without encountering a failed installation may put the components in an inconsistent state.