Adobe Reader DC/Outlook issue

Hi all,

I have a user in my organization experiencing an odd issue. She had this issue on a previous Win 7 pc with Outlook 2010 and is now experiencing it again on a new Win 10 pc with Outlook 2016. Her Outlook will completely lock up/freeze when sending an email. She had a pdf open in Adobe Reader vers 19.010.20069. Once I closed the open pdf in reader, Outlook unfroze and returned to normal. I tried to find some diag info in Windows Event Viewer but could not find anything. Has anyone encountered this before?