How can I fix the 'onSectionLoad' error in Boost theme?

Topic summary

A user is encountering a theme warning error in the Boost theme for Shopify. The error message appears to be reversed text that reads: “Theme warning: ‘onSectionLoad’ failed for section ‘header’”. This suggests a JavaScript callback function (onSectionLoad) is failing to execute properly for the header section of the theme. The issue likely stems from:

  • A JavaScript error in the theme’s section loading mechanism
  • Corrupted or missing theme files
  • Conflicts with third-party apps or custom code

The discussion remains open with no solutions provided yet. Troubleshooting steps would typically include checking browser console for detailed error messages, reviewing recent theme modifications, and verifying theme file integrity.

Summarized with AI on November 23. AI used: claude-sonnet-4-5-20250929.

We are using Boost theme in our application. We are getting below error. How can i debug this error?

Theme warning: 'onSectionLoad' failed for section 'header'