Seems that ever since I installed Avast on my Macbook Air (Sierra v10.12.1), some, but not all, emails sent to me containing HTML do not display the HTML stuff properly, just the web links. Before installing Avast I didn’t have this issue, so I’m sure it’s Avast that’s causing it. I use MacMail as my email client. Any suggestions?
Lets try to narrow down the issue further. In the Avast Preferences, disable the WebShield. Then close and relaunch the Apple Mail client. See if the HTML images display normally. If not, go back into preferences, enable the WebShield and disable the Mail Shield and test again.
Report back which shield was the issue and we can go further.
Ok, I’ve tried both suggestions but it didn’t work. At least emails that I had already received didn’t display HTML. Not sure if it will only work on new emails? Other suggestions? And thanks for helping!! 
Other suggestions?Any help in this? https://www.google.no/webhp?sourceid=chrome-instant&rlz=1C1JZAP_noNO713NO713&ion=1&espv=2&ie=UTF-8#q=MacMail+does+not+display+html
Update: Did an email rebuild as suggested by many in the link shared by Pondus and it seems to have worked. One day does not a trend make, but i’m hopeful. So, maybe it wasn’t an Avast issue – in which case I apologize for mucking up this forum. But clearly I got to someone who could help. Thanks all! ;D
Hi Laura,
Let us know if everything still looks ok.
Mac