Blank space in emails

User reports that some emails have a large chunk of blank space in the middle. He gets an email - with some of the email at the top , and then a several pages of blank space and then the signature at the bottom.

Any ideas how to fix.

Thanks.

Subject: blank space in emails

every e-mail? just from certain users? sent via automated process? received from internet? help us out with more info.

Subject: RE: blank space in emails

Any external internet mail is fine. But emails within our company are not.