This is definitely your best bet. Were you using an iPhone or an iPod Touch in that time window? Maybe iTunes still has a backup of the device in its backups fo

This is definitely your best bet. Were you using an iPhone or an iPod Touch in that time window? Maybe iTunes still has a backup of the device in its backups folder? If you were using Mail.app, also check your Mac's Mail Downloads folder. It's totally possible the attachment was downloaded and not deleted when the email was. On my machine, that folder is full of ancient files for some reason. Also if you power on any old devices to look for the email, put them in airplane mode ASAP!