Beginning with OS X 10.6 the Apple Mail started copying names in addition to the address when you copied address to the clipboard. This tweak reverts the behavior to only copy the e-mail address.
Start a new Terminal session (in Finder click Applications > Utilities > Terminal).
To disable this setting, type (or copy and paste) the following command:
defaults write com.apple.mail AddressesIncludeNameOnPasteboard -boolean false
To reset this setting to the default value, type (or copy and paste) the following command:
defaults write com.apple.mail AddressesIncludeNameOnPasteboard -boolean true
To activate this tweak please close all instances of Mail, or wait until the next reboot.
Close the Terminal session by typing
exit at the prompt.
Disclaimer: Making any changes to your system can cause serious problems that may require you to reinstall your operating system. We cannot guarantee that problems resulting from these modifications can be resolved. Please follow the instructions carefully and use the information provided at your own risk.