PRB: Rollback from MDAC 2.6 Service Pack 2 Refresh Fails

Rollback of the Microsoft Data Access Components (MDAC) 2.6 Service Pack 2 (SP2) Refresh may fail under the following circumstances:

• Install of Microsoft SQL Server 2000 SP2
• Install of MDAC 2.6 SP2 Refresh Release
• Rollback of MDAC by running "dasetup /u" at the command line

Under these circumstances, some of the MDAC files that are installed on the computer are MDAC version 2.6 (2.60.6526.3), and some of the files are MDAC version 2.6 SP2 (2.62.7926.1). See the "More Information" section of this article for details about how to determine which version of MDAC you currently have installed. You can obtain MDAC file lists for each release in the release manifest that is posted with the download for the release at the following Microsoft Web site:

This problem occurs because of the reversioning of components in the MDAC 2.6 SP2 Refresh Release. For additional information, click the article number below to view the article in the Microsoft Knowledge Base:

To work around this problem, use one of the following methods:

• Reinstall the MDAC 2.6 SP2 Refresh Release.
• Install the MDAC 2.7 Refresh Release.

This behavior is by design.

For additional information about a problem that occurs when you upgrade from MDAC 2.6 SP2 (which is included with Microsoft SQL Server 2000) to MDAC 2.7 RTM, click the article number below to view the article in the Microsoft Knowledge Base: Because of this problem, Refresh releases have been made for both MDAC 2.6 SP2 and MDAC 2.7. When you use either of these Refresh releases, you do not experience the issue that is described in the Knowledge Base article Q314755. However, the MDAC 2.6 SP2 Refresh release is not designed to install over MDAC 2.6 SP2. If you have a computer with an existing MDAC 2.6 SP2 installation and you want to upgrade to MDAC 2.7 RTM, use the MDAC 2.7 Refresh installer to avoid the upgrade issue.

To determine the state of the MDAC installation through Microsoft Windows, use the Component Checker tool. To obtain this tool, visit the following Microsoft Web site:
Component Checker can determine which version of MDAC most closely matches the current state of your installation, and lists each file that is not the correct version. For more information about using the Component Checker tool, see Component Checker Help.

For more information about MDAC Installation, rollback, and the Component Checker tool, see the white paper that is located at the following Microsoft Web site: