As long as I’m on the subject of Apple Mail, I might as well throw this tip out there too.
Most Mac users would like nothing better than to only exchange files with other Mac users. Unfortunately, that is just not the case. Most, if not all of us have to interact with PC people too.
In Apple’s Mail application, there is one setting that for some reason is OFF be default, but it should be ON, in order to have the most compatibility with PC users.
If you use the Attach button on a new mail message, you are given a checkbox to select “Windows Friendly Attachment”. But if you drag a file onto the message window to attach it, you are not given that option. But, there is a way to turn on that option for all outgoing attachments regardless of how you attach the file to the message. Simply go under the Edit menu and select Attachments > Always Send Windows Friendly Attachments. That’s all you have to do.
Doing this doesn’t decrease the attachments compatibility with other Mac users, it simply increases the files compatibility with PC users.
On a side note to this, the files you send to PC people should always have the file extension in the name (.pdf, .doc, .psd, etc…). PCs rely on that file extension to know what type of file it is.