August 03, 2013
Here’s the first fix I always try after W3 Total Cache starts serving blank white pages when I browse my site after updating WordPress. These instructions assume you know your way around the WordPress and W3 Total Cache admin areas.
To test for the blank screen issue, be sure to view the site in Chrome’s Incognito mode or Firefox’s Private Browsing mode without logging into the admin area. Logging into the admin area creates cookies for storing your session, and W3 Total Cache will not serve cached pages to users who are logged in (unless you change it in W3 TC’s Page Cache configuration).
Also note that W3 TC will inject some extra comments into your page to give you debugging info. You can see it by viewing the source. This is a good way to check if Page Caching is enabled when you load a page. Here’s a sample:
!-- W3 Total Cache: Page cache debug info: Engine: disk: enhanced Cache key: kb.imakewebsites.ca/_index.html Caching: disabled Reject reason: User is logged in Creation Time: 0.768s Header info: X-Pingback: http://kb.imakewebsites.ca/xmlrpc.php Expires: Wed, 11 Jan 1984 05:00:00 GMT Cache-Control: no-cache, must-revalidate, max-age=0 Pragma: no-cache Content-Type: text/html; charset=UTF-8 X-Powered-By: W3 Total Cache/0.9.2.11 X-W3TC-Minify: On --
This bug appeared for me today moving from WordPress 3.5.1 to 3.6 with W3 Total Cache 0.9.2.11 on a DreamHost server (I’m not sure what versions of PHP and Linux and MySQL it uses). I’ve seen it happen on other hosts like an EC2 instance hosted on Amazon with Ubuntu when moving between other versions of WordPress as well.
In my experience, the blank pages are always caused by the Page Caching functionality (with Disk: Enhanced caching method). Try following these steps to get your pages back:
If Page Caching works now that you’ve uninstalled, reinstalled, and reconfigured W3 TC, you can continue by turning on other parts of W3 TC and testing they work. If not, use the W3 Total Cache Support boards to find a solution to your problem.