After updating your Mac to Mountain Lion, you might receive one of the following messages if you try to install older HP printer software designed for previous versions of Mac OS, either from an original product CD or from HP Software & Driver Downloads.
'HP Installer can't be opened because it is from an unidentified developer'
Figure : Example of the 'HP Installer can't be opened...' message
'Unsupported Operating System'
Figure : Example of the 'Unsupported Operating System' message
'This HP software may not be compatible...'
Figure : Example of the 'HP software may not be compatible...' message
To resolve these messages, continue with the instructions in this document to install the updated HP software for Mountain Lion using Apple Software Update.