You need to fully uninstall the previous version of StoreMI before installing the current updated StoreMI.
The older version of StoreMI leave back the drivers on the system even after you have uninstalled it... due to which the current StoreMI doesn't allow you to uninstall it.
You need to uninstall the older version of StoreMI drivers from the system and then try installing the latest StoreMI.
Note: If you has fused the OS Drive with SSD with old StoreMI then better don't uninstall the drivers as that will cause the system not to boot back.
If your Primary drive (OS Drive) was used in creation of StoreMI then its should be relatively safe to uninstall previous storemi drivers (will be seen some thing like Entier drivers under Storage controllers), after that reboot and proceed with New StoreMI installation.
