I looked at causes for the white screen of death in WordPress today. Of course, the first thing is to turn on WP_DEBUG in config.php. This could produce a lot of clutter as there are many plugins – and even parts of core – that use deprecated functions. But never mind.
In my case, I was uploading a theme I am creating that uses some functionality (widgets) that I had originally put in a plugin. So now that code was double:
Fatal error: Cannot redeclare ccb_load_widgets() (previously declared in
Uh-oh. Facepalm. Redeclaring functions is a major cause of WordPress giving up with a white screen. Hope this is of any use to anyone.
Here is a good article on themefoundry about the issue.