I am using a developer edition of SQL Server 2008 deployed in Windows 7 Professional SP1. Pursuant to instuctions given for a DBA course I took, I created a second instance using the SQL Server setup wizard. After the class was finished, I used the same setup wizard to remove the instance. The procedure failed with the error message: "Value cannot be null. Parameter name: sddlForm". The removal procedure corrupted the instance to the point where it can neither be reactivated. The SQL Server now cannot be updated, such as with the recent service pack update, which fails due to the presence of the non-functional instance.
I have already read the information posted at the following location: https://connect.microsoft.com/SQLServer/feedback/details/587143/sql-2008-uninstall-value-cannot-be-null-sddlform. I seems to refer to the identical situation, unfortunately it does not provide enough information to fix the problem:
Thank you for bringing this to our attention. The scenario where the SID was being chnaged was not being correctly handled in the Filestream uninstall/configuration logic. This has been addressed in the next version of SQL Server.This information may be intelligible to a Microsoft engineer, but is otherwise useless. What is a group SID? I did my best to read through the numerous and verbose installion logs and could not identify that value. Which log is it in. Where in the registry would you put it, assuming you are able to find it?
To workaround the uninstall failure, we suggest trying to change the group SID back in the registry and uninstall again. The original Group SID should be available in your oiginal install logs for the instance.