SQL Server 2008 R2 upgrade and INSTALLSHAREDDIR/INSTALLSHAREDWOWDIR

I recently found myself trying to upgrade an old SQL Server 2008 R2 instance to SP3 so that it could in turn be upgraded to SQL Server 2014, but quickly ran into problems with the following error message:

The INSTALLSHAREDWOWDIR command line value is not valid. Please ensure the specified path is valid and different than the INSTALLSHAREDDIR path.

At first I thought this would be pretty simple – fire up setup.exe from the command line and manually specify the INSTALLSHAREDWOWDIR and/or INSTALLSHAREDDIR options, but that would have been far too easy and unfortunately it seems that for whatever reason you can’t specify these options when the action is “patch” (update/upgrade) or “repair” – they only work for “install”, which wasn’t going to help me.

Much Googling later I had found plenty of people with similar issues, but most were struggling with initial installation (it seems that the SQL Server 2008 R2 installer was very buggy at first) rather than upgrading/updating or repairing an existing installation and so none of the fixes provided worked for me.

Eventually, after poking around the registry, I discovered that the installer is looking in the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Installer\UserData\S-1-518\Components\0D1F366D0FE0E404F8C15EE4F1C15094 key for the INSTALLSHAREDDIR path as well as the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Installer\UserData\S-1-5-18\ Components\C90BFAC020D87EA46811C836AD3C507F key for the INSTALLSHAREDWOWDIR path.

All of the values in the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Installer\UserData\S-1-5-18\ Components\C90BFAC020D87EA46811C836AD3C507F key (INSTALLSHAREDWOWDIR) were fine (“C:\Program Files (x86)\Microsoft SQL Server\”), but one of the values (91D3749D1F6219B4BBCA0498BC14CB84) in the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Installer\UserData\S-1-518\Components\0D1F366D0FE0E404F8C15EE4F1C15094 key (INSTALLSHAREDDIR) was set to “C:\Program Files (x86)\Microsoft SQL Server\” instead of “C:\Program Files\Microsoft SQL Server\” and so the INSTALLSHAREDDIR path was conflicting with the INSTALLSHAREDWOWDIR path.

Updating the 91D3749D1F6219B4BBCA0498BC14CB84 value from “C:\Program Files (x86)\Microsoft SQL Server\” to “C:\Program Files\Microsoft SQL Server\” allowed the SP3 update to complete successfully with no reboot require for the change to take effect and I was then able to complete the upgrade to SQL Server 2014 successfully.