Author Topic: [RESOLVED sort of] Multi-part MIME Email Stripped of text/html contents  (Read 577 times)

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Offline LLG-Steve

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My office and I are experiencing a problem where emails appear to be blank in Apple Mail.

What I can diagnose is that on the GMail server, the messages are Multi-part MIME with a text/plain section and a text/html section.  Using the GMail web interface, I can see the contents of the message, and in the Show Original, I can see the plain and html sections fully populated.

On the desktop Apple Mail, the html section is stripped of everything except the MIME Boundary identifiers and contents identifiers:

Code: [Select]
Content-Transfer-Encoding: quoted-printable
Content-Type: text/html; charset=us-ascii


If Avast stripping out everything between <html> and </html> by accident?

macOS: 10.13.6 (and others)
Apple Mail: Version 11.5 (3445.9.7) (and others)
Avast Security 14.6 (0ee7f50937ff)
« Last Edit: October 20, 2020, 10:02:55 PM by LLG-Steve »

Offline LLG-Steve

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Re: Multi-part MIME Email Stripped of text/html contents
« Reply #1 on: October 19, 2020, 10:36:14 PM »

Messages that contain ONLY a text/html MIME section display correctly on the GMail web and in Apple Mail.

Offline ondrej.kolacek

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Re: Multi-part MIME Email Stripped of text/html contents
« Reply #2 on: October 20, 2020, 11:27:13 AM »

We did make changes to Mailshield in Avast 14.6 to make it compatible with MacOS Big Sur. We have tested the GMail + Apple Mail combination extensively and have not encountered the reported problem at all. We can not reproduce this on your configuration - MacOS 10.13 with Apple Mail 11.5 and last version of Avast. Mail which contains both text/plain and text/html mime parts is correctly delivered and displayed without problems.

Please if this is happening to you, notify us about it in this thread, so we can gauge how widespread this problem is, and send us a support package ( with description mentioning this thread. Workaround is to disable Mail Shield component for the time being.

To the OP, please check your mail.

Kind regards,
Ondrej Kolacek
(ondrej.kolacek <at>

Offline LLG-Steve

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Sort Of Resolution
« Reply #3 on: October 20, 2020, 10:04:59 PM »
So, after some additional in-depth testing, we have determined that the error occurs ALSO when the Mail Shield is turned off.  As such, it's likely that Avast is not the source of the problem. 

Additional testing continues, but this thread is likely at its end.

Thank you everyone.