How do I get rid of the lines in Outlook ?

As you all noticed before, email platforms like Outlook, Gmail, AOL, etc.  render emails differently from one platform to another. 

One of the most frustrating rendering email bugs is the "1px line bug".

The 1px line bug is a design bug that happens only on the Outlook email platform. This bug causes a  line to appear between campaign blocks.

Outlook will add extra lines to your emails. These lines will inherit the background set on your <body> tag, often causing the issues illustrated, above. To make matters worse, this bug seems to happen at random, although it does appear more regularly on Windows 10 machines, compared to Windows 7.

For example: 

Email on Acid Email Footer

Although there is no explanation to this odd behavior, the leading theory is that it has to do with heights that are odd numbers. If we discover any new information, we’ll be sure to update this support article.

How can I fix this?

Unfortunately, there isn’t a hard-and-fast rule for fixing this bug. However, there are some steps you can take to try and minimize its effect on your email:

1. Adjusting Heights and Font Sizes

In some cases, changing font sizes from odd numbers to even numbers can solve this issue. For example, if you have a font size of 13px or 15px, try converting it to 14px.

You can also try manually changing heights, font sizes and line-heights to achieve the same outcome.

2. Matching the Background

Considered more of a workaround than a fix but still effective. 

The lines inherit the color from the body of the email (<body> tag). By setting the background color of the email to the same color as our problem section would cover up the lines. Even though they are still there, your recipients won’t see the lines.

3. Segmentation

We are aware that this issue is coming from Outlook and not on other email platforms. That means that there’s no need to change the background color of email clients that render the email correctly.

Creating a segment of Outlook users to target in differently designed campaigns can help you avoid sending emails with the lines. 


For email design issues and requests, contact 


Other solutions to this issue can be found in the articles below:




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  • Your system can't segment by device used to view emails.


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