How we migrated off the Thesis WordPress Theme on a site using the WP e-Commerce Plugin.

Start point: Thesis 1.8, WPEC 3.7.8, WordPress 3.2.1
End Point: Elegance 1.4.5 , WPEC, WordPress 3.4.1

The Thesis theme and the WP-eCommerce plugin do not tend to work well together. As a result we’ve been unable to upgrade a clients ecommerce site using WPEC because of various issues encountered due to the incompatibilty of Thesis and WPEC.

In order to uprgrade we needed to select a replacement theme for Thesis to run the store. The essential requirement was that it is WPEC compliant. After looking at several themes we chose Elegance from Storefront Themes.

After upgrading the development site in the ‘normal’ manner we encountered problems where some CSS was being loaded from several places causing inconsistant page layouts (the page would be part old style part new style). This was particularily noticeable on the checkout page.

After investigating the problems we restored the service to its previous state and started again. The following process was followed and resolved all our issues (not all steps below are mandatory and there’s probably some flexibilty in the order)

(1) Activate theme 2010.
(2) In the WPEC settngs under the Presentation tab ensure the (WPEC) Theme is set to “Default Theme”.
(3) Remove Thesis theme and any Thesis specific plugins (eg. Thesis OpenHook)
(4) Flush theme cache and basic site check.
(5) Upgrade WPEC (decativate current version, ftp up latest version and activate)
(6) In webhosting (or using ftp) rename folder /uploads/wpsc/themes to another name (eg. themes-hide)
(7) Flush theme cache and basic site check.
(8) Install and activate new theme (Elegance 1.4.5 in our case).
(9) Flush theme cache and basic site check.
(10) Configure new theme.
(11) Upgrade to the latest WP release.

We tested this process twice and didn’t encounter any issues. If you find any broken links you should try re-saving your Permalinks settings (twice). The key steps for us seemed to be (2) and (6) – without those we were getting some CSS loaded by the theme and some loaded (iShop) by WPEC . After following the process above all CSS was loading from the correct locations. This worked for us but may or may not work for you. As always, before making updates take backups and test it first in a development service.