PSCONFIG trying to access wrong DLL in GAC?

Question

TL;DR

Uninstalling SharePoint 2010 and installing SharePoint 2007 makes PSCONFIG stop running since it misses the Microsoft.SharePoint.DLL version 14. How can this be solved?

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On a SharePoint 2010 server SharePoint was uninstalled. The 14-hive was manually removed and the SharePoint Web Sites and IIS was deleted. Upon installing SharePoint 2007 SP 2, everything went fine until the final step – running PSCONFIG. We got the error message from the console stating

C:\Users\SP_Setup>psconfig

Unhandled Exception: System.IO.FileNotFoundException: Could not load file or assembly 'Microsoft.SharePoint, Version=14.0.0.0, Culture=neutral, PublicKeyToken=7
1e9bce111e9429c' or one of its dependencies. The system cannot find the file specified.
File name: 'Microsoft.SharePoint, Version=14.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c' ---> System.IO.FileNotFoundException: Could not load file
or assembly 'Microsoft.SharePoint, Version=12.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c' or one of its dependencies. The system cannot find the file specified.
File name: 'Microsoft.SharePoint, Version=12.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c'

WRN: Assembly binding logging is turned OFF.
To enable assembly bind failure logging, set the registry value [HKLM\Software\Microsoft\Fusion!EnableLog] (DWORD) to 1.
Note: There is some performance penalty associated with assembly bind failure logging.
To turn this feature off, remove the registry value [HKLM\Software\Microsoft\Fusion!EnableLog].

   at Microsoft.SharePoint.PostSetupConfiguration.Common.SetThreadCultureToInstalledCulture(Thread thread)
   at Microsoft.SharePoint.PostSetupConfiguration.Common.SetCurrentThreadCultureToInstalledCulture()
   at Microsoft.SharePoint.PostSetupConfiguration.PsconfigCommandLineMain.Main(String[] args)


C:\Users\SP_Setup>

What puzzles me is the way PSCONFIG tries to access Microsoft.SharePoint.DLL version 14 in the first FileNotFoundException. Is there a reference somewhere that we didn’t think of when we uninstalled SharePoint 2010, that couldn’t be resolved upon installing SharePoint 2007? Is there a way to fix this or should we bluntly reinstall the entire Windows Server 2008 R2?

Answer 1

This is probably not the recommended, nor the supported way to do it. The best would probably be to reinstall Windows Server 2008. However, in my case, it solved the problem and could be used as a last resort if you can’t reinstall the server. I opened the regedit and searched for ”14.0.0.0” and found these interesting posts:

I updated the path from 14 to 12 the following way on all locations:

Further, I changed the regedit ServerRole from SINGLESERVER to APPLICATION to be able to specify Database Server in the following location:

“HKLM_Local_Machine/Software/Microsoft/Shared Tools/Web Server Extensions/12.0/WSS/”