When I was trying to uninstall SQL Server 2008 from my machine, I received the following error message:
At a glance, this error may seem to be something critical, but it is not. It’s something quite silly to be honest. When you install SQL Server 2008 on a 64 bit machine, it installs SQL Server for both x86 and x64 compatibility, leaving two separate items under Control Panel -> Programs and Features, as shown below:
If you try to uninstall by clicking on first one (above 64-bit one), then you will get this rule mismatch error. You must select the second one (64-bit one) to successfully uninstall.
When I selected the appropriate one, my uninstall validations passed without hassles.