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USE CASE Target

Fix Max-Width Constraint Collapsing in Apple Mail (Desktop) — HubSpot Guide for eCommerce Campaigns

In eCommerce email marketing, rendering issues directly tank conversion rates and cart recoveries. Product grids, checkout CTAs, and discount banners must display flawlessly to prevent purchase drop-offs. Below is the targeted integration guide to fix Max-Width Constraint Collapsing inside Apple Mail (Desktop) templates when using HubSpot.

Technical Breakdown

Apple Mail (Desktop) uses the WebKit which lacks support for standard rendering rules. This causes Max-Width Constraint Collapsing elements to break or collapse when rendering templates.

HubSpot Behaviors

HubSpot's COS template manager automatically wraps content blocks in dynamic div structures to support their drag-and-drop system. These extra wrappers force styling inheritances that override inline td paddings, leading to spacing collapses in Outlook. Setting explicit table element attributes is crucial. Double-check your dynamic product feed blocks. When injecting product loops from your catalog, ensure width sizes are explicitly handled to keep columns from overlapping.

Remediation Code Block

To secure design widths, always wrap your layout inside a parent table with a static, hardcoded HTML width attribute (e.g. width='600') targeting Microsoft clients using conditional comments. In your HubSpot campaign manager, make sure you configure your links to run via {{ unsubscribe_link }}.

<!--[if mso]>
<table role="presentation" align="center" border="0" cellpadding="0" cellspacing="0" width="600">
  <tr>
    <td>
<![endif]-->
<div style="max-width: 600px; margin: 0 auto;">
  Centered Layout Content
</div>
<!--[if mso]>
    </td>
  </tr>
</table>
<![endif]-->

Live Code Sandbox Test

Interactive HubSpot Custom Sandbox

Target Environment: Apple Mail (Desktop)

How to Deploy inside HubSpot

1

Copy the fixed VML or table wrapper code block from the remediation box above.

2

In HubSpot's Design Manager, edit the modules section. Create a 'Rich Text' or 'HTML' module block. Double-click the block, choose 'Tools' or 'Advanced', click 'Source Code', and drop the code snippet inside.

Targeted Fixes by Use Case & Industry