Viewing TNEF Emails. Core integration

A constant pain in the modern work environment is the winmail.dat files in tnef emails So I’m wondering if anyone is looking into this bug from all the way back from 2001. I can’t just ask government employees and other clients to reconfigure their email clients (often they can’t because of IT lock down) and Lookout (fix version) dosn’t let lightning see event invites (big issue for my boss)

I was encouraged by reading this recent conversation but it does boil down to maybe

In the past for that I was using a linux solution with a little program homemade to extract this kind of files.

Unfortunately I don’t have direct access to the email server otherwise I would set up and automatic conversion.

I attempted to use the addon FiltaQuilla and the python library tnefparse however I couldn’t extract any files with that library. Using cygwin to get the tnef project working is just not practical for all our work computers.

This is just something that NEEDS to be built into a modern mail client. Because Micro$oft is gonna Micro$oft

Would this addon help?

No, the plugin doesn’t really help. Event’s aren’t seen by Lightning and the current version isn’t working properly (can’t actually save the files to disk). I’m using an old version for now so I can pull files… usually

Hi Ryan. lookout-fix-version is working ok in most situations. The thing is that the developer seems to have abandoned it and the addon is not compatible with versions of TB after 58 (i.e. 60 betas). In order to work one hass to deactivate addon compatibility checking but even then, the configuration dialog simply doesn’t work.
unfortunately tnef encoded messages are very common in business environments and as dugite-code mentions, there’s no use advising users to configure outlook as this is not an option for them in most cases.

What is the source of these TNEF emails. You say they are very common, but my understanding is Microsoft has not shipped a version of Outlook using TNEF for internet email for around a decade. Perhaps some of the corporate users involved need a reply quoting the Microsoft knowledge base.

Problem: Recipient receives the Winmail.dat attachment.
Solution: Turn TNEF off (either for the recipient, or globally).

Problem: Recipient receives the ATT00001.DAT attachment.
Solution: Turn TNEF off (either for the recipient, or globally).

Problem: Recipient does not receive regular file attachments.
Solution: Turn TNEF off (either for the recipient, or globally).

Problem: Recipient does not have Voting buttons in Outlook.
Solution: Turn TNEF on for the recipient.

Problem: Recipient receives meeting requests as regular messages.
Solution: Turn TNEF on for the recipient.

Problem: Recipient does not receive custom form information.
Solution: Turn TNEF on for the recipient.

Problem: Recipient does not receive formatted message text.
Solution: Turn TNEF on for the recipient.
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Hello Matt
I don’t know for others but in my case tnef encoded emails originate from different companies, mostly multinational ones with local branches here in Greece and I suppose the users are using old versions of outlook, or their IT has a policy of enabling tnef (I can’t say though, why someone would choose to have such a policy).
I understand that the effort to support a legacy technology may be disproportionate and I wouldn’t even mention it if a workaround could be found. For the time being, as I mentioned before, lookout-fix-version seems to do the job although incompatible with 60beta versions. I’m afraid though, that this will not be the case for 60 release or for next releases and, in any case, having incompatible addons installed is not a good practice as they can be the source for unpredictable problems.

Unfortunately, I don’t have the required knowledge to undertake the maintenance of this addon.

Anyway, closing this, if someone has to suggest a workaround (other than notifying the users to disable tnef) It would be more than welcome.

I’m mostly getting TNEF emails from local government organizations that recently had brand new email servers set-up.

Maybe they had an auto-convert function set on the old one. Unfortunately my boss is adamant we can’t send them any emails telling them they have incorrectly set up emails so I’m stuck and the old plug-in is quite broken at this point, I can’t save files without using the detach function and drag and drop doesn’t work with it either.

  • Edit: It looks like a few organizations we deal with have started sending the win.dat files after this never being an issue before. I’m starting to suspect they were relying on the server to do the conversion and haven’t set this up again.

  • Edit2: On Thunderbird 52.9.1 rolling the Lookout (fix) addon back to Version 1.2.18 fixes the save-all function.

Ok with the release for TB 60 and the fact I couldn’t find the authors email I’ve been poking around in Lookout’s code to see if I can get it to work properly.

Currently I’ve fixed the Transparent preferences dialogue and the save all function. This should keep my coworkers relatively happy for now.

Is there any good tutorials for addon development? I have a sinking feeling I’m only getting started

Sorry to revive, one of the first hits on Google.

Been testing for a while with this. It seems to stem from either:

  1. Contacts in Outlook with old settings that have format set to RTF (you can do this on a per contact basis…)
  2. Have the issue with skype meetings for example. Not sure if they’re related to the previous point however.

If I forced contact to HTML format mail, the meeting part was text/calendar in the source. That works just fine.

Anyway, to fix globally on Exchange, run:
get-remotedomain | set-remotedomain -TnefEnabled:$false

That should have Exchange rewrite all mail going out to all domains to not have TNEF.

Proprietary formats suck :wink: