SQL Server Cumulative Update uninstallation fiasco. Dude, can I remove SQL Server setup files?
We have been struggling to uninstall the Cumulative Update package 7 on a development SQL Server!
As it is an important aspect of installation to rollback or to have a backout plan tested if you are performing any kind of installation against your Production Server, not to mention its a best practice too. Until now most of the Microsoft programs are designed to uninstall easily using Add/Remove programs from the Control panel, but it seems this isn't quite right for these Cumulative Updates on SQL Server 2005 SP2. Within the MVP community too I have been told do not attempt to uninstall these updates in the same fashion and worth to mention about SQL Server Service Pack or Hotfix patch or Cumulative Update: do not attempt Windows System Restore as a backout plan? blog post here, as I have seen many users out-there are taking this route!
So after a discussion the solution was advised by Microsoft support (CSS) that if you leave old setup files (SQL Server 2005) for previous Cumulative Update, for instance if you are trying to uninstall CU7 then you must have CU6 related setup files on the Server where the SQL Server installed. I felt this is a wierd concept that you have such a Single-Point-Of-Failure (SPOF) dependancy whereby most of the times the DBA would go and delete the files once the setup has been completed on the live SQL Server instances.
Before speaking to the CSS we have been finding a way to uninstall the old fashion way which was unsuccessful, where by it was hanging round with an hourglass to show and not moving any bit further. Couple of times other colleagues mentioned to reboot the server or kill that uninstall process via Task Manager, which is another bad(worst)-practice you may develop if you are not getting relevant results. Obviously I have turned down to go that route as it may potentially leave the system in a inconsistent/bad state. So as per the general practice we have deleted the previous CU setup files and going forward decided to allocate a seperate drive to have the installation files other than keeping them on C: drive whereby you will not have much space allocated when the server is designed to install.
During the recent interaction with Microsoft Product group & CSS team we have been told that a KBA will be provided about how to rollback or deal the uninstallation process within Hotfix and Cumulative Update installations.