Winmail.dat attachments being received by SOME users. - Email and calendar - Office 365

Hi - I'm using Outlook 2011 for Mac. Since changing my exchange server to MS365, certain users are receiving any attachment I send as a winmail.dat file.

I need to be able to send these users attachments as part of running my business, so it's critical I just get this fixed and not have a hundred workarounds! Sending via plain text makes no difference either btw. I have compose set to html as standard though.

I use a Mac with 10.7.4

Can anyone assist with what setting needs to be changed to resolve this please?

TIA

Hi Ron Edwards,

Thanks for your post. Based on the description, the problem could be related to TNEF Message Formatting. I'd like you can take a look at help.outlook.com/.../gg263346.aspx for the detail information and solution.

Thanks, Neo Zhu

Hi Ron,

Can you use another computer with the Windows platform to resolved this issue?

Thanks, Neo Zhu

Not really, I'm a Mac user?! All we use in the office and at home.

Hi Ron,

Do you mean the is no Windows platform computer can be used for the Powershell ? If so, my suggestion is you can use OWA (http://mail.office365.com/) for a walk-around solution.

Thanks, Neo Zhu

OK, thanks, what settings do I change in OWA for this to work?

Hi Ron Edwards,

You don't need to anything on OWA. Just use it as a web outlook application.

Thanks, Neo Zhu

You're kidding right? Your solution to this problem is that I stop using a Microsoft program and use OWA. Tell me that's a joke please

Hi Ron,

My first step is use Powershell to change the setting of your Office365 tenant to resolve this issue (you can also see the detail steps in the help article). However there is no Windows platform computer can be used on your side. (Only available is the Mac Computer )
So, my second step is use OWA as the walk-around solution.

If you have consider about the solution, maybe you can forward this link to your colleague who available to use Powershell. This setting mentioned in article is a global setting, can be modified to every admin in the Office365 tenant.

Thanks, Neo Zhu

Hi Ron,

How are you doing? I am just writing to see if there is any progress on this issue. I do not mean to push you. I just want to ensure that you do not encounter any problems during the troubleshooting. Thank you.

Neo Zhu

See my reply above. If your only fix is that I no longer use Outlook for Mac, a Microsoft product and have to use OWA, well that's hardly a solution now is it.

I have now been able to get access to a Windows computer. It would seem however that this solution is only for a computer running windows and using Outlook? Or can I somehow access the exchange server and change settings there?

Hi Ron Edwards,

Thanks for getting back. Now, we need to do is use Powershell to connect Exchange online service and change the setting. You cna take a look the following information:

1, Connect Exchange online via Powershell help.outlook.com/.../cc952755.aspx

2, RUN "Set-RemoteDomain Default -TNEFEnabled $false"

Thanks, Neo Zhu

I have al the powershell set up, but how do I connect to 365 exchange?

This is what the link tells me:

In the Windows PowerShell Credential Request window that opens, type the credentials of an account in your cloud-based organization. When you are finished, click OK.

Run the following command:

Copy

$Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri ps.outlook.com/powershell -Credential $LiveCred -Authentication Basic -AllowRedirection

Note The AllowRedirection parameter enables cloud-based organizations in datacenters all over the world to connect Windows PowerShell to the cloud-based service by using the same URL.

Run the following command:

Copy

Import-PSSession $Session

A progress indicator appears that shows the importing of commands used in the cloud-based service into the client-side session of your local computer. When this process is complete, you can run these commands.

Where and what details go in?

Thanks