Troubleshooting Theme Tests

Running into issues with a theme test? This guide covers the most common problems and how to fix them.

A third-party app isn't working on the variant theme

Some Shopify apps inject code or use app blocks that are configured per theme. When you duplicate your theme for testing, the app may need to be set up separately on the variant theme.

How to fix it

1. Open your variant theme in the Theme Editor (Online Store > Themes > Customize on the variant).

2. Check that any app embeds are toggled on in the App embeds section.

3. Check that app blocks are present in the same sections and templates where they appear in your live theme.

4. If the app has its own settings dashboard, verify that it recognizes and is configured for the variant theme.

Some apps store their configuration at the store level and work across all themes automatically. Others are theme-specific. If you're unsure, check the app's documentation or contact their support team.

I accidentally edited my live theme instead of the variant

If you made changes to your live (control) theme instead of the variant, those changes affect all visitors immediately, including those not in your test.

How to prevent it

Before editing, always confirm which theme you have open. In the Shopify Theme Editor, the theme name appears at the top of the editor. Your variant theme will have a different name from your live theme (for example, "Theme Test — New Header v2").

How to fix it

1. Undo immediately if you're still in the Theme Editor. Use Ctrl+Z (Windows) or Cmd+Z (Mac), then click Save.

2. If you've already saved and closed, manually revert the changes by editing your live theme back to its original state.

3. If you're not sure what changed, check your theme's version history: go to Online Store > Themes > ... > View version history.

Shoplift is redirecting me away from theme previews

Shoplift includes safeguards that redirect visitors away from unpublished theme previews under certain conditions. After a theme test ends, Shoplift redirects any visitors still on the variant theme back to the live theme. It also redirects untracked visitors who are viewing a theme preview, because they could be real shoppers who shouldn't be on an unpublished theme.

These safeguards can sometimes interfere with normal theme development workflows, like previewing an unpublished theme in your browser or sharing preview links with your team.

How to exclude yourself from redirects

Append isShopliftMerchant=true to your theme preview URL. This tells Shoplift that you're a merchant, not a visitor, and disables the redirect behavior for your browser.

Your preview URL should look like this:

https://your-store.myshopify.com/?preview_theme_id=1234567890&isShopliftMerchant=true

This also works for:

• Preview links you share with teammates

• Incognito browser windows

• Automated testing tools like Selenium or Puppeteer

How to re-enable redirect behavior

To reset the merchant flag and re-enable normal redirect behavior, add the parameter with a value of false:

https://your-store.myshopify.com/?isShopliftMerchant=false

How to check your current merchant flag

If you need to verify whether the merchant flag is set in your browser:

1. Open your browser's developer tools (Cmd+Shift+C on Mac, Ctrl+Shift+C on Windows).

2. Click the Application tab (in some browsers this is called Storage).

3. Expand Session Storage in the left sidebar and select your store's domain.

4. Look for an item called Shoplift_Session. The isMerchant attribute inside it shows your current value.

My theme test was automatically paused

If Shoplift paused your theme test automatically, it's usually because a new page was published with a template that doesn't exist in your variant theme. Shoplift pauses the test to prevent visitors from landing on a broken page.

For example, if you create a new product template called product.holiday in your live theme and assign products to it, but your variant theme doesn't have a product.holiday template, visitors assigned to the variant would see an error on those pages. Shoplift catches this and pauses the test.

How to fix it

1. Add the missing template to your variant theme. The easiest way is to copy the template content from your live theme: go to Online Store > Themes, open the Code Editor on your variant theme, and create the missing template file. Then copy the code from your live theme to your variant theme.

2. Back in Shoplift, open the paused test. You'll see an error modal explaining which templates are missing.

3. Click Recheck theme in the modal. Shoplift will verify that the variant theme now has all the required templates.

4. Once the check passes, resume your test.

To avoid this issue, add any new templates to both your live theme and your variant theme before assigning pages to them.

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Still need help? Contact Shoplift support.