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cant open attachments of ppt and excel

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I had updated my Thunderbird to 60.3.2 few weeks ago and ever since I cant open attachments of excel and powerpoint sent via email. The pptx and attachments are getting converted to winmail.dat or office xml handler and not opening.

When I open the same emails in webmail I can open these attachments.


Can you please advise how to resolve

I had updated my Thunderbird to 60.3.2 few weeks ago and ever since I cant open attachments of excel and powerpoint sent via email. The pptx and attachments are getting converted to winmail.dat or office xml handler and not opening. When I open the same emails in webmail I can open these attachments. Can you please advise how to resolve

All Replies (4)

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When folk send emails from outlook it tried to use the proprietary Microsoft TNEF format. Thunderbird does not have a license to use TNEF. So just contact your senders and ask them to send real email not Microsoft proprietary stuff.

https://support.mozilla.org/en-US/kb/what-winmaildat-attachment

The article talks about an add-on and links to it, but it has not been updated to support Thunderbird versions after 12. So I guess the author has abandoned it.

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Hi Matt the same people have been using the same software even earlier and now. These are people with who I have daily email interaction. While thunderbird responded earlier and all attached files could be opened but not after their last update.

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You mention winmail.dat. That tells you everything about the problem. The sender maybe using the same Outlook program, but they or an update has changed some settings in Outlook so that it is not sending emails in a compatible format. They are only sending emails in a format that other Outlook users can use. They need to change those settings as advised by Microsoft. see link at bottom of page.

The Microsoft Outlook e-mail program sometimes sends e-mails in the Transport Neutral Encapsulation Format (TNEF). Most other e-mail programs, including Thunderbird, do not understand TNEF.

If your e-mail program doesn't understand TNEF, instead of seeing the e-mail and/or attachment, you may only see an attachment named "winmail.dat" or "Part 1.2" that you cannot open. Also, sometimes you may receive a TNEF attachment with a generic name such as ATT00008.dat or ATT00005.eml instead.

The sender can avoid sending TNEF attachments by by turning off TNEF in Outlook. When Outlook is configured to send e-mail in "Outlook Rich Text Format", it may use TNEF. When it sends in "HTML" or "Plain Text", it uses standard, compatible formats.