There is a known issue with attempting to email directly from AccountEdge to Mac Mail on Mac OS X 10.11 El Capitan. The PDF of the invoice or purchase, etc. will not be attached to the email when sending directly from AccountEdge. This only occurs in Mail and does not occur when sending emails through Outlook.
Update now available
An update is now available to fix this issue if you're using the following AccountEdge versions:
AccountEdge Pro/Network Edition v14.5 (Australia)
AccountEdge Pro/Network Edition v14 (New Zealand)
AccountEdge Basic v3
You should be prompted to install the update when you open AccountEdge.
If the prompt doesn't appear when you open AccountEdge, go to the AccountEdge menu and choose Check for updates.
If no update is available
If no update is available, you're probably using an older AccountEdge version which isn't supported on OS X 10.11 El Capitan (see above for the compatible versions).