Hi Paul,

Thanks for responding.

My thought process here is that Outlook / Microsoft are the biggest email software providers in the world. They aren't going to change/update their systems because a QuickBooks email doesn't render properly.

FYI - The issue isn't to do with browsers or mobiles. Just the desktop version of Outlook 365.

I've had a look and I do not see an option of sending QuickBooks invoice emails in plain text. 

I could download PDF's and send manually. But QuickBooks invoices would only stay in 'draft mode' if I don't send the invoice. The other option is to send the email from QuickBooks and then resend via my own email account. So defeats the objective. And looks poor sending an invoice twice. And adds a lot of extra time to manually email my invoices. The whole point of QuickBooks having the Invoicing system is to save time.

Thanks