The patch
installation is blocked if any existing system files (files that are
targeted to be updated by a patch) have changed and cannot be related
to previous versions of the patch. This ensures that operating system
files that change due to other explicit system administrator action
(for example, layered product patches or non-dupatch installed CSP installations) are not inadvertently overwritten.
You must take special action, through the baseline feature to enable
patch installation in this situation.