Why am I unable to send/receive MAT files (.mat) over email?

I am attempting to send/receive one or more .mat files attached to an email, but they are being blocked. I see the following warning:

Outlook blocked access to the following potentially unsafe attachments: myReceivedFile.mat

Why is this the case and are there any workarounds for the issue?

Answer 1

[MathWorks Support Team]

By default, Microsoft Outlook flags file attachments with the extension ".mat" as potentially unsafe. This is because the software treats .mat files as "Microsoft Access Table Shortcuts", a filetype that can occasionally be harmful. See here for more information on blocked file types:

https://support.microsoft.com/en-us/office/blocked-attachments-in-outlook-434752e1-02d3-4e90-9124-8b81e49a8519

If the recipient of your email message is using Microsoft Outlook as an email client, this is most likely why they are unable to view any .mat file attachments.

To workaround this issue, you can try one of several options:

1. Compress the .mat file(s) into a zipped file and send it to your recipient.
2. Edit the extension of the .mat file to be ".txt" and inform the recipient to revert the name to "filename.mat" after receiving it.
3. Use a secure file transfer system instead of email routed to Outlook.

For other possible workarounds or customizing the workaround for your setup, please consult with your local IT department.