Machine Certificate authentication is used on MAC OS X clients. During the GlobalProtect connection process, the user needs to enter the Local Administrator account credentials to allow access to the System keychain twice.
When using Machine Certificates with GlobalProtect on Mac OS X Clients, the certificate must be accessed from the "System" keychain in MAC OS X. This will cause a Keychain Access prompt to appear twice when the client attempts to access the certificate for verification against both portal and gateway.
Open the Keychain Access application and locate the Machine Certificate issued to Mac OS X Client in the System keychain.
Right-click on the private key associated with Certificate and click Get Info, then go to the Access Control tab
Click '+' to select an Application to allow
Press key combination <Command> + <Shift> + G to open Go to Folder
Enter '/Applications/GlobalProtect.app/Contents/Resources' and click Go
Find PanGPS and click it, and then press Add
Save Changes to private key
The steps above allows GlobalProtect access to only THIS certificate and private key. It will no longer prompt for keychain access, giving users a seamless, no-touch experience with Palo Alto Networks GlobalProtect.
The procedure has to be done again every time client is updated.