Clients unable to open emailed invoices.Comes up as a windat.mail. Is it a Reckon set up problem.

LEANNE_10540167

Invoices emailed not able to be opened.  sent as windat.mail ?? worked from windows 7 but not windows 10

Zappy

You need to change your email prefs to send as plain text. If you send as html it gets blocked. 

Thanks for your question

Rav

Just to add to Kevin's reply, there's a help article that gives a general overview on this particular message here -
Winmail.dat rather than invoice or statement attachment is received by some email recipients

Datarec

This may help too How to turn off TNEF to prevent recipients getting WINMAIL.DAT attachments for Outlook for Office 365