Concrete CMS 9 · Updated 2026-09-03
Removing a theme is the install steps in reverse, with one ordering rule: you cannot cleanly remove the theme your site is currently using.
Activate a different theme before you remove anything. Atomik's files ship with every Concrete 9 install, so it is the usual landing spot. If your site was installed from the Elemental starting point, install Atomik first under Pages & Themes, then activate it:
./vendor/bin/concrete concrete:theme:activate atomikFrom the Dashboard, uninstall it under Extend Concrete. From the command line:
./vendor/bin/concrete c5:package:uninstall castUninstalling removes everything the package registered: the theme record, and any page templates or block types it added. Only then delete the folder from packages/.
Pages keep their content and their blocks. What they lose is the template those blocks were arranged for. If the removed theme registered a page template, say left_sidebar, and another installed theme also provides one with that handle, pages carry on rendering. If nothing provides it, those pages fall back and their sidebar content stops appearing.
Before removing a theme, list which pages use its templates so you can reassign them deliberately.
Do not. Deleting a package directory while the package is still installed leaves database records pointing at files that are gone, and the Dashboard reports a missing package instead of letting you tidy up. If you have already done it, put the folder back, uninstall properly, then delete.