This topic

Winmail.dat issues with btinternet.com

scusack — Mon, 13 May 2024 11:04:58 GMT

So this is one that I cannot find a fix anywhere. Two client companies (different people each time) sent emails with attachments that always arrive as winmail.dat on Outlook 365 (latest update on Windows 11), also on the BT Mail website, but OK on my iPhone's email. None of the suggestions already online work, so please don't suggest trying a fix that I've already tried half a dozen times over the last 2 years.

Why does it only happen with BTinternet.com? I have 4 other email addresses (not BT) and the attachments work OK with them, using the same copy of Outlook 365.

Re: Winmail.dat issues with btinternet.com

gg30340 — Mon, 13 May 2024 11:28:04 GMT

My and I am sure other forum member crystal balls are not working so perhaps you could enlighten us what fixes you have tried so that we don't try to "suggest trying a fix that I've already tried half a dozen times over the last 2 years".

Re: Winmail.dat issues with btinternet.com

Jane2018 — Mon, 13 May 2024 11:29:42 GMT

I sometimes have the same problem on my other email address too and in those cases (very few people send me .dat files) I just forward them to my hotmail email (yet another email I have) which can open them without any problems.

Re: Winmail.dat issues with btinternet.com

scusack — Mon, 13 May 2024 11:38:42 GMT

Here is a selection of websites that I've referred to. However if any other website mentions winmail.dat please be assured there's a very strong possibility I've already read it and tried it's suggestions over the last 2 years. It only happens with these two clients (major corporations) and only with the BTinternet.com (and btopenworld equivalent) email address.

https://www.lifewire.com/prevent-sending-winmail-dat-attachments-1173717

https://www.secureax.com/blog/fix-winmaildat-attachment/

https://answers.microsoft.com/en-us/outlook_com/forum/all/why-i-am-getting-email-attachments-as-winmaildat/b2b2427d-1e86-496a-b2c0-d130fa622ade

https://answers.microsoft.com/en-us/outlook_com/forum/all/why-i-am-getting-email-attachments-as-winmaildat/0f882a97-6c7e-4a80-96ba-4c0cf3e72dfa

https://discussions.apple.com/thread/252764097?sortBy=best

Re: Winmail.dat issues with btinternet.com

scusack — Mon, 13 May 2024 11:40:12 GMT

Once it's received as a winmail.dat file, forwarding them on to an alternative address simply forwards the winmail file, it doesn't unpack it.

Re: Winmail.dat issues with btinternet.com

gg30340 — Mon, 13 May 2024 12:05:42 GMT

For test purposes are you able to take your Outlook 365 out of the equation in order to see what format the extensions arrive at your BTMail webmail account as?

Re: Winmail.dat issues with btinternet.com

scusack — Mon, 13 May 2024 12:22:03 GMT

OK I shut down Outlook. Then I arranged for an email with an attachment to be sent to me. I opened my BT webmail on Chrome, and the attachment was there as a winmail.dat file. Nothing to do with my Outlook.

Re: Winmail.dat issues with btinternet.com

gg30340 — Mon, 13 May 2024 12:27:19 GMT

Ok. I doubt there is anything that the forum users will be able to do to resolve this so I have notified the moderators of the forum about your problem. Once they have read this they may be able to help or pass the problem onto the BTMail email team. They will advise you by posting on this thread.

Re: Winmail.dat issues with btinternet.com

DavidM — Mon, 13 May 2024 12:39:13 GMT

Hi @scusack and thanks for posting.

This is a bit of a mystery and I'm not sure there's anything we can do to help but we'll be happy to try. Check your inbox for my message and drop me over the details.

Cheers

David

Re: Winmail.dat issues with btinternet.com

Anonymous — Mon, 13 May 2024 12:45:36 GMT

The mention of clients suggests this is, or should be, a business email account?

Re: Winmail.dat issues with btinternet.com

licquorice — Mon, 13 May 2024 13:44:52 GMT

The problem lies with the sender.

Re: Winmail.dat issues with btinternet.com

gg30340 — Mon, 13 May 2024 14:08:02 GMT

@licquorice wrote:

The problem lies with the sender.

I would agree but the OP stated he was receiving the attachments on his iPhone without any problems which would tend to indicate that they are being sent out correctly.

Re: Winmail.dat issues with btinternet.com

scusack — Mon, 13 May 2024 15:21:22 GMT

I can also receive them if they are sent to a different email address using the same outlook 365 programme on my laptop, but yes you are correct, if they come to my iPhone they are readable.

Re: Winmail.dat issues with btinternet.com

licquorice — Mon, 13 May 2024 15:48:02 GMT

Everything is a bit vague at the moment can you clarify the following.

Are the problem attachments being sent from just a small number of senders or from everyone sending?

What file format are the attachments, are they .PDF for example?

Are attachments of the same format received ok from other users?

What mail application is the sender using to send the problematic attachments?

Re: Winmail.dat issues with btinternet.com

scusack — Mon, 13 May 2024 15:55:42 GMT

Everything is a bit vague at the moment can you clarify the following.

Are the problem attachments being sent from just a small number of senders or from everyone sending?

Anyone within that organisation (I'm assuming going through the same server)

What file format are the attachments, are they .PDF for example?

Word, pdf, meeting invitations, PPT

Are attachments of the same format received ok from other users?

Yes

What mail application is the sender using to send the problematic attachments?

MS Outlook, however it is all of the senders from the two organisations, not an individual Outlook account. I checked with two of them, and they say that "message format" is set to "when sending messages in rich text format to internet recipients convert to HTML format"

Re: Winmail.dat issues with btinternet.com

licquorice — Mon, 13 May 2024 16:10:29 GMT

It would appear to be a combination of the sender using a non standard method of attaching the files and btinternet email not handling it gracefully somehow, which seems totally weird as you are using a third party client to receive the mail rather than BT webmail.

Can you definitely confirm if the emails are sent to a Gmail address (say) and collected by the same client your end, they are received ok?

Re: Winmail.dat issues with btinternet.com

licquorice — Mon, 13 May 2024 16:14:01 GMT

Scratch that, it has to be Outlook 365 your end not handling it correctly as your iPhone app is ok.

As an experiment, can you try a different mail client to Outlook 365 temporarily. Thunderbird or EmClient for example.

Re: Winmail.dat issues with btinternet.com

scusack — Mon, 13 May 2024 16:15:21 GMT

Can you definitely confirm if the emails are sent to a Gmail address (say) and collected by the same client your end, they are received ok?
Yes, although I can't say it for Gmail as I don't use it. However if sent to one of my other email addresses which are frequently MSExchange, they always come across as expected.

Re: Winmail.dat issues with btinternet.com

scusack — Mon, 13 May 2024 16:17:43 GMT

As an experiment, can you try a different mail client to Outlook 365 temporarily. Thunderbird or EmClient for example.

I'll try this tomorrow, thank you for your help. I have to attend a family event now

Re: Winmail.dat issues with btinternet.com

gg30340 — Mon, 13 May 2024 16:23:56 GMT

@licquorice wrote:

Scratch that, it has to be Outlook 365 your end not handling it correctly as your iPhone app is ok.

As an experiment, can you try a different mail client to Outlook 365 temporarily. Thunderbird or EmClient for example.

See messages 6 & 7 where he took Outlook 365 out of the equation and only used BTMail webmail to receive the attachment.