There is a thin line appearing in my template when I insert into Outlook

When using Outlook 2016 (for Windows), you may experience a bug in Outlook that causes a thin line to appear in your template when inserted. In most cases, this is a 1 px white line that appears throughout the template. In every case that we have discovered online, and from other HTML email experts, these lines have the color of the background. 

We are continuing to investigate with other experts in the HTML email field to see if there is a solution to this issue that ensures random lines don't appear when using different backgrounds and content colors.

The current workaround is to ensure your email body background and main content background have the same color you won't see the issue. Read on for some other tips:

Why does this happen to my email?

  • Zoom options on Outlook Desktop: These issues are commonly visible when users are zoomed in on the email, as 1px spacing is relative to the device view.
  • Stacked image borders: If you have several images on top of each other, Outlook will sometimes add a border surrounding an image or element. Ensure borders are set to 0 to avoid this.
  • Image size: You may be using images with more pixels to retain image quality on larger screens. Ensure your image size is divisible by two with no decimals to ensure no stray pixels. For example, opt for an image that is 200 px by 200 px, rather than 205px by 205px. 


  • set background to white
  • add an empty row: this may even out the pixels across the email
  • Splice images into even pixel width and height
  • if using tables, ensure max height does not exceed 700px
  • simplify your email structure: avoid stacked images and multiple content columns in the same row 

Please contact your Account Manager for more information if you are experiencing this issue. 

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