We are plagued with random situations where emails coming with inline attachmnets are not showing in outlook 2010 If attachments. Forward the message to a different mail provider , for example yahoo mail  the exact same messages show attachments as expected! So in other words, the attachments really are there but for some reason when the messages come through the Office365/Exchange 2013 server Outlook 2010 won't show them and the message has to be forwarded to a different email system to get at the attachments.

Await reply from Microsoft 

Hi

As per the information and details provided by you, to solve the Outlook attachment problem, please follow these steps: -

All versions of Outlook include a security feature that blocks attachments that might put your computer at risk for viruses or other threats. You can still open the attachments that Outlook blocks by using one of the following methods: -

1. Use a file share to access the attachment.
2. Use a file compression utility to change the file name extension.
3. Rename the file to have a different file name extension.

Follow these steps to save the attachment and rename it to use the original file name extension:

• Locate the attachment in the e-mail.
• Right-click the attachment, and then click Copy.
• Right- click the desktop, and then click Paste.
• Right-click the pasted file, and then click Rename.
• Rename the file to use the original file name extension, such as .exe.

4. Ask the Exchange server administrator to change the security settings.

I hope this information will be helpful for you.

Thanks and regards

Shweta@G

Hi,

If we login to OWA and check on the emails, are these attachments still hidden?

Based on my research, this issue occurs when Exchange Server does not validate whether there is a reference to the inline attachment. If the inline attachment is not referenced, the inline attachment is hidden.

To resolve the issue, you can try the following steps:

1. Stop the Exchange Transport service.

2. Locate the EdgeTransport.exe.config file. This file is located in the following path:

<drive> :\Program Files\Microsoft\Exchange Server\Bin\

3. In the EdgeTransport.exe.config file, add the following entry between the <appSettings> element and the </appSettings> element:

<add key="TreatInlineDispositionAsAttachment" value="true" />

4. Restart the Transport service.

Since we focus more on Outlook client side issue, if you have any problem when performing steps above, you can post a new question in Exchange forum:

https://social.technet.microsoft.com/Forums/exchange/en-US/home?category=exchangeserver

Regards,

Steve Fan
TechNet Community Support