How to resolve possible errors installing SQL Server 2005 SP1 related to the Setup Support Files

I heard from a customer recently who had an issue installing SQL Server 2005 SP1 (here for Express Edition or here for non-Express Editions) on a system that had multiple editions of SQL 2005 installed. They indicated that they were encountering the same issue as the one described in this bug report on the product feedback site.

The good news is that the bug report provided a workaround that solved this customer's issue, but the bad news is that the workaround steps listed in the bug report proved to be confusing, and they were only able to resolve the issue after I clarified the steps. As a result, I'm going to try to summarize the workaround in the bug report in more specific detail so that if anyone else runs into this issue, you'll hopefully be able to figure out how to resolve it on your system as well.

Here are the steps that you should be able to use to resolve SQL Server 2005 SP1 setup issues related to the Setup Support Files:

1. Click on the Start menu, choose Run and type regedit
2. Navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\90\Bootstrap\MSIRefCount
3. Rename the Uninstall value to Uninstall2
4. Click on the Start menu, choose Run and type appwiz.cpl
5. Uninstall the product named Microsoft SQL Server Setup Support Files
6. Locate and install the MSI named SqlSupport.msi from the original installation media for SQL Server 2005
7. Click on the Start menu, choose Run and type regedit
8. Rename the Uninstall2 value back to Uninstall
9. Try again to install SQL 2005 Service Pack 1

Hopefully this will make the steps listed in the bug report more clear in case anyone else runs into this SQL 2005 SP1 setup issue.....

• Anonymous
  June 18, 2014
  It works as well for Error 29527 when installing SQL Server 2005 SP4 fails. Great! Thanks a lot!

• Anonymous
  December 18, 2014
  fixes the issues installing service pasks on sql 2005 to me too thanks !!!