Drupal has no way to uninstall a theme using the user interface, however there are times when you might really need to do this, such as clearing out old themes you no longer need, or when issues present due to upgrades.
UPDATE: there is now a simple module to help with the removal of old database entries: http://drupal.org/sandbox/jmburnz/1685382
For example, during the development of Adpativetheme 7.x-3.x some theme settings changed, this can cause some notices and warnings to appear after upgrading from one version to another (such as moving from RC1 to Dev) and even make some settings fail to appear - the easiest and fastest way around this is to do a clean install of your sub-theme. You will loose your theme settings - this is a small price to pay really, its pretty easy to reconfigure your theme and you can totally sidestep a lot of small issues simply by doing a clean install.
Note this does not fully remove things such as block or color configuration settings - the idea here is to perform a clean install of the theme settings, so we want to keep any block settings, color settings etc that might be saved, so you don't have to reconfigure all your blocks, which could be a lot of work.
Its as fairly basic process, and followed carefully anyone can do this; it only takes a few minutes.
1. Make sure the theme you are removing/upgrading is disabled. If you are upgrading Adaptivetheme core first set Bartik to be default and disable your sub-theme (and AT Core if you have it enabled).
2. Next you need to delete two database rows. Go into the database and find the "variable" table. In this table you will find two rows pertaining to your theme - they follow these naming conventions:
For example if you are using the Corolla theme, the rows are named:
You can manually delete these using phpMyAdmin user interface tools, or run these these two queries using the SQL tab in phpMyAdmin:
delete FROM variable WHERE name = "theme_corolla_settings";
delete FROM variable WHERE name = "theme_corolla_files_directory";
3. Next clear the sites cache.
4. Now you can add the new code, such as upgrading AT Core, or remove those old themes you don't want anymore.
5. If you have upgraded AT Core you can now re-enable your sub-theme, then go to the theme settings and save them again.
Last updated 16th July, 2012 - 4:58pm