Modify Mac OS X Guest Account

1 Login in as guest

2 Customise your guest space. Modifiy the Dock, change Desktop, etc...

3 Once you've modified the guest account as desired, close all apps.

4 Be sure to delete things like browsing history (you were surely looking at that webpage for guidance, and had safari open.)

5 Next, switch users (don't log out) into your admin account.

Open Terminal and do the following:

            (guest account must be active otherwise you can not "cd /Users/Guest/")

sudo -s

cd /Users/Guest/

rm -R /System/Library/User\ Template/English.lproj/Library/

cp-R Library/ /System/Library/User\ Template/English.lproj/Library/

go back to Guest User and log out

Open Terminal and do the following:

sudo -s

mv '/System/Library/User Template/English.lproj/Library/Keychains' '/System/Library/User Template/English.lproj/Library/Keychains.old'

mkdir '/System/Library/User Template/English.lproj/Library/Keychain