A recent MS Office 2016/365 patch broke the Act!/Outlook integration, preventing email history from being created and causing Act! to crash when trying to email from Act! For more information please see the statement from Swiftpage below.
Happily a simple work-around has just been posted on the Act! forum. If you are affected by the Office 2016/365 problem, hopefully this will work for you while we wait for a permanent solution from either Microsoft or Swiftpage.