If your email's borders or section edges look misaligned after sending — even though the design looked correct in the Email Builder — the cause is almost always Classic Outlook's rendering engine. Classic Outlook displays emails with Microsoft Word, which handles borders, padding, and width differently from other email clients. This article explains why it happens and how to fix uneven borders and row widths.
These issues appear in Classic Outlook only. The same email usually looks correct in New Outlook, Outlook on the web (OWA), and other clients.
Symptoms This Article Covers
- Rows that extend beyond the header, footer, or neighboring sections
- Borders that appear thinner than you set them
- Alignment that differs between Classic Outlook and New Outlook or OWA
Why Borders and Rows Misalign in Classic Outlook
Classic Outlook renders emails with Microsoft Word's engine, which calculates borders, padding, and layout differently from modern email clients. A border adds to a section's displayed width, so a row with heavier or mismatched borders can render wider than the rows around it.
Classic Outlook limits border thickness to 8px. If you set a border thicker than 8px, Classic Outlook displays it at the 8px limit, which can make borders look thinner than you intended.
How to Fix Uneven Borders and Row Widths
Make one change at a time, then re-test, so you can see what each change does.
- Compare the border thickness, placement, padding, and background colour of the misaligned row against its neighboring rows.
- Reduce any border thicker than 8px to 8px or less.
- Match the side-border settings across rows where the edges should line up. Check how this affects any full-width images in those rows.
Borders are set at the row and column level in the Properties menu. Make sure you're comparing the same level across rows — a border applied to a column behaves differently from one applied to a row.
Verify Your Fix
- After each change, send yourself a test and open it in Classic Outlook
- Compare the result with New Outlook or Outlook on the web
- Review the mobile layout after any structural change
Still Misaligned? Escalate to Support
If the rows still don't line up, reach out to our support team and include:
- The email's JSON file
- Screenshots of the received email (not the Email Builder preview)
- Your Outlook version