Upgrade to 3.0 Failed, Website with White screen of death WP-admin inaccessible

Try adding this to wp-config.php: define('WP_DEBUG', true);. This will turn on error reporting and display, if your server supports it, and may reveal the issue.

Next, try renaming your plugins directory, which will deactivate all of your plugins. If that works, then move it back and you can activate your plugins one by one until you find the culprit.

After, still no dice, try a manual upgrade.

deactivate all plugins works for me, thank you

I wanted to confirm that I had the same problem with a Blank Screen and renaming the plugins directory worked to get things running. Then I moved the plugins into the valid “plugins” folder one at a time to find the offending plugin.

The bug is caused by WordPress Admin Bar plugin.

Fix:
1) Rename the plugin folder
2) Login in admin
3) Rename plugin folder for the original name
4) Active plugins but NOT active WordPress Admin Bar plugin.

I tried renaming my plug in folder and following the above steps, but am getting the following error still:

Warning: call_user_func_array() [function.call-user-func-array]: First argument is expected to be a valid callback, ‘__return_zero’ was given in /home1/happyhe8/public_html/wp-includes/plugin.php on line 166

Fatal error: Call to undefined function is_multisite() in /home1/happyhe8/public_html/wp-login.php on line 85

Any insight is greatly appreciated!!

Same problem here. Upgrade went smoothly, but after logging out and logging in again, all I get is white…

Hi ilanaz, you should perform a manual upgrade (see Upgrading WordPress). It looks like the auto-upgrade failed to copy over the 3.0 wp-includes/functions.php file.

Found my problem (I think):

In functions.php I added

<?php

if ( function_exists('register_sidebar') )
	register_sidebar(array(
        'before_widget' => '<li id="%1$s" class="widget %2$s">',
        'after_widget' => '</li>',
        'before_title' => '<h3>',
        'after_title' => '</h3>',
    ));

?>

<?php

add_theme_support('menus');

?>

As you can see the add_theme_support has its own set of php opening and closing tags. Putting just the line add_theme_support(‘menus’) inside the already existing tags solved my white screen. I didn’t know this could make such a difference…

Yep… functions.php gets included everywhere, even in wp-admin, and any whitespace in this file will prevent WordPress from, for example, redirecting to wp-login.php when you try to access yoursite.com/wp-admin directly, as it cannot send the proper redirection code back to the browser since output (the whitespace) has already been sent.

For files like wp-config.php and your theme’s functions.php, it’s best to open the PHP tag once, and forget it, as in don’t bother closing it. (They don’t need to be closed.)

Thanks for the explanation. I already saw that the functions.php file was not closed with ?>. I thought it was forgotten by the developers ;).

Anyway (and this is offtopic, I know), I read throught the new functions.php of the new theme twentyten and find it rather complicated. At least for someone who develops themes (layouts) for customers (like me), but is not so good with php. I hoped the functions.php could have been filled with widget like code snippets to add functions one needed.

We definitely didn’t aim low with Twenty Ten. Some of the files are quite rich in PHP. Additionally, the functions for translation that wrap every string give it a bit more complexity. While it isn’t a beginner’s theme, we are able to demonstrate a wide range of features, and it is also chock full of comments to try to explain what goes on, which I hope helps a little.

How do i do all this stuff in the FTP?

Just thought I’d chime in that I ran into the same problem.

Clicked the auto-updater (which has worked absolutely flawlessly for me for a couple years now) and instantly got the “Down for maintenance, check back in a minute” message.

After that, white screen of death.

Tried to update the config file… didn’t work.
Opened the functions file in Dreamweaver… yeah, no.

Ended up doing the manual updgrade.
1. Delete wp-includes and wp-admin
2. Upload WP3.0 files, overwrite when prompted

Site is back.

(whew!)

Still love WP.