Mountain Lion: Mail stops responding when adding an EPS attachment
When adding an EPS attachment to a Mail message, Mail may stop responding until you quit and reopen it.
As a workaround, use a different attachment type, or access your email account through a web browser and attach the file.
Alternatively, first compress the EPS file and then attach the compressed (.zip) version of that file to the Mail message. To compress it, select the .eps file in the Finder and then choose File > Compress.