...it exists between Word and Outlook.
Stop using Word as your email editor. To get advanced text enhancements make sure your Outlook /options/mailformat is chosen as "HTML" (turn off/uncheck "Use Word as your email editor"). This will allow bold/italics, etc... but it will stop *you from using two programs to edit one pc. of email... both of which have to access some of the same OS files simultaneously, a problem which manifests more often on larger files, file attachments and/or embedded pictures. Unfortunately you'll then have to run MS Spelling check seperately, but.
Also, if you are using filesharing/networking/or a camera chip reader... never attach a file from any place other than (a copy on) your local drive... anything else are the ingredients in a recipe for disaster.
... plus what everyone else says, but.
"...anything else are" = I can't wait to hear about that usage... 
