Didn't work for me. Just wanted to let you guys know. Tried disabling Forefront manually, but that didn't help.
Action 23:33:18: CA_CUSTOMER_PREPATCH_INSTALL.
CAQuietExec: Error 0x80070001: Command line returned an error.
CAQuietExec: Error 0x80070001: CAQuietExec Failed
CustomAction CA_CUSTOMER_PREPATCH_INSTALL returned actual error code 1603 but will be translated to success due to continue marking
Action 23:33:19: CA_ROLLBACK_SAVEDATA_STOP_SERVICES.
Action 23:33:19: CA_START_WMI_SERVICES_ROLLBACK.
Action 23:33:19: CA_ENABLE_WMI_SERVICES_ROLLBACK.
Action 23:33:19: CA_SAVEDATA_STOP_SERVICES. Stopping services
CAQuietExec: Error 0x80070001: Command line returned an error.
CAQuietExec: Error 0x80070001: CAQuietExec Failed
CustomAction CA_SAVEDATA_STOP_SERVICES returned actual error code 1603 (note this may not be 100% accurate if translation happened inside sandbox)
Action ended 23:33:31: InstallExecute. Return value 3.