Before installing CA Service Catalog 12.9 cumulative patch on already installed / Uninstalled environment, locate the registry entry of an earlier installed version in your system and delete the Version folder.
To delete the registry entry, complete the following steps:
1.Navigate to the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\CA Service Catalog\Version folder.
2.Delete the Version folder.
3.Reboot the server and retry the patch installation.