I saw that similar type of issue already been asked here, http://www.coffeecup.com/forums/responsive-email-designer/possible-bug-w-and-if-mso-comments/.

However I faced same issue ([if !mso] comments code visible in the mail here and there) with following email programs.

Windows 7 Professional - Windows Live Mail
Windows 7 - Lotus Notes

Above email programs are currently being reported by our newsletter clients after sending our very first responsive newsletter.

As @JB-LGD said, the other fallbacks are hiding correctly, e.g.: <!--[if gte mso 9]> , only issues are with the [if !mso].

I have attached the screenshots of the forward newsletters from our clients for your reference.

Any help would really appreciated.

Thanks
Janith

Hello Janith,

In this case it seem the platform you are using for sending is changing the code. In the app we are using instead of the we see in your screenshots. What sending platform are you using? Can you attach the project file so we can check? W7 / Live Mail does not give any problems here...

Hello Bob,

I am using https://sendgrid.com/ as our email provider.
I checked my template and it is using , So I feel your guess may be correct.

However I have attached the the project file for your reference.

Thanks
Janith

Hey Janith,

Everything with the project code looks good to us. Have you tried to send to these email programs directly from RED?