Periodically, my colleagues and I will work on a pre-existing document, change grammar and formatting, but when we save the document, the changes disappear. The often happens when the file is uploaded to email. The changed files reside correctly on our computers, but the sent changes disappear.
@Frank_McEvoy You should not open the document directly from the email message. Rather, you should save it to the local drive and then open it from there, after first right clicking on it and then on Properties and checking the "Unblock" box.