What are all those junk CSS files in site/files/css with names like css_ZFCUUB6IIfaVQ-erWDr0M0Na1JbxEsU-8zjQrWAtrbU.css? There are hundreds of them.

How do these get generated over time? What do they do?

2 Answers 2


They aren't junk files, they are aggregated files are generated when you have CSS aggregation turned on. They make your page load times faster, as multiple files are aggregated into a single file, meaning less files have to be downloaded to the browser.


Yes @Jaypan is right. You need to check on admin/config/development/performance. In the Bandwidth optimization section there is an option for Aggregate and compress CSS files. Deselect that option and save, if you want to remove them.

Clear the cache and check.

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