Windows live mail crashes when sent with attachments

Windows live mail 2011 crashes when attachments are sent in a reply, to a customer in either excel or .pdf format. I have researched this and can't find the answer. I have repaired 2011, uninstalled it and re-installed several times.

I tried 2012 essentials and it was no better. Can this be a particular setting, or the way my customers email is formatted. This problem only started this past July when I went to I.E. 10. Continued in I.E. 2011.

As always ..... your help is appreciated.