LESS File Is Empty Error During CSS Generation with Pearl Theme

Problem

When running php bin/magento weltpixel:css:generate (or php bin/magento weltpixel:less:generate), the process fails with an error similar to:

Compilation from source: LESS file is empty:
frontend/Pearl/weltpixel_custom/en_GB/WeltPixel_CategoryPage/css/weltpixel_category_store_default.less

This error typically appears after one or more of the following:

• Migrating from a manual (SSH/app/code, app/design) installation to a Composer-based installation
• Switching the active storefront theme to Pearl or a Pearl child theme
• Setting up a store view with a non-default locale (e.g., en_GB)

The root cause is that certain WeltPixel modules generate store-specific LESS files dynamically (for example, weltpixel_category_store_STORECODE.less). These files are created when module settings are saved in the Magento admin or when the LESS generation command is run. If they have never been generated for a given store view — or if generated files were removed during a migration — they will be empty or missing, causing compilation to fail.

Solution

Follow the steps below in order.

Step 1 — Ensure the Pearl base theme is installed via Composer

If you migrated from a manual installation and removed files from app/code or app/design, confirm the Pearl base theme is present as a Composer package:

composer require weltpixel/m2-theme-frontend-weltpixel

Important: If you maintain a custom child theme in app/design/frontend/Pearl/weltpixel_custom, do not also install weltpixel/m2-theme-frontend-weltpixel-custom via Composer. Having the same theme registered in both locations causes a duplicate theme definition error. Choose one location only.

Step 2 — Regenerate store-specific LESS files via Magento admin

This is the most reliable way to populate the empty store-specific LESS files:

1. Log in to the Magento admin panel.
2. Navigate to Stores > Configuration and open each of the following sections for your affected store view. Re-save the settings (no changes required — saving alone triggers LESS regeneration):

• WeltPixel > Category Page settings
• WeltPixel > Product Page settings
• WeltPixel > Frontend Options settings
• WeltPixel > Custom Header settings
• WeltPixel > Custom Footer settings

3. After saving, navigate to System > Cache Management > WeltPixel Cache Management and click Re-Generate Pearl Theme LESS/CSS.

Alternatively, you can trigger LESS regeneration for all covered modules at once via CLI:

php bin/magento weltpixel:less:generate

Step 3 — Clear generated and static files

Remove stale generated files to ensure a clean compilation:

rm -rf generated/*
rm -rf pub/static/*
rm -rf var/view_preprocessed/*

Step 4 — Run the standard Magento deployment sequence

php bin/magento setup:upgrade
php bin/magento setup:di:compile
php bin/magento setup:static-content:deploy -f en_GB en_US
php bin/magento cache:flush

Replace en_GB en_US with the locales used by your store views.

Step 5 — Regenerate WeltPixel CSS

php bin/magento weltpixel:css:generate --store=STORECODE

Replace STORECODE with your actual store code (e.g., default). Run this command once per store view that uses the Pearl theme.

Step 6 — Re-save theme and layout configuration in admin

If Luma or another parent theme's styles continue to appear after compilation, force Magento to refresh its design configuration:

1. Go to Content > Design > Configuration.
2. Click Edit for the affected store view and re-save without making changes.
3. Return to Stores > Configuration and re-save the WeltPixel > Category Page settings, paying particular attention to category display layout options (e.g., Full Width, One Column).
4. Flush the cache: php bin/magento cache:flush

Verification

The fix is successful when:

• php bin/magento weltpixel:css:generate --store=STORECODE completes without any LESS file is empty errors.
• The storefront displays Pearl theme styling with no Luma fallback styles visible.
• Store-specific LESS files (e.g., weltpixel_category_store_default.less) are no longer empty — you can confirm by checking the file size inside the relevant module's view/frontend/web/css/ directory.

Updated on: 09/03/2026