WordPress MU

I upgraded to 2.8.1

The blogs show fine (ublog2.com & pumpkinslayer.com both running on same code), site/wp-login.php shows fine, but after login, all pages in the backend are blank.

No PHP errors, just totally blank pages.

I've disabled all mu-plugins and normal plugins, but still nothing. I'm perplexed.

Any suggestions on what to try next?

Do you have access to your PHP/Apache error logs?

I've seen the same problem (blank dashboard). See http://trac.mu.wordpress.org/ticket/1053 for a possible solution.

Thanks James

It ended up not being any of these (although I did uninstall all themes and plugins before discovering my particular problem).

It was actually a database issue.

At some point in the past, probably quite a while ago, certain entries in the database that were escaped, became non-escaped, and that never made a difference until now.

I run multiple sites off a single install, so I needed to update these escaped values, which included the list of site_admins. I found that only on more recently created sites could I login, which made me suspect this.

Anyways, the effected values in the "wp_sitemeta" table are the meta_values "site_admin", "menu_items" and "allowed_themes"

This probably only applies to old installs, pursue other methods to fix blank admin area first (mine's been around since there was still the wp-inst dir), fresh ones shouldn't have this problem.

Step-by-step to update these....

In PHPAdmin....

Use a search like this (replace ' with ` in the following):

SELECT * FROM 'wp_sitemeta' WHERE ('wp_sitemeta'.'site_id' = 2 OR 'wp_sitemeta'.'site_id' = 3 OR 'wp_sitemeta'.'site_id' = 4 OR 'wp_sitemeta'.'site_id' = 5 OR 'wp_sitemeta'.'site_id' = 6 OR 'wp_sitemeta'.'site_id' = 7 OR 'wp_sitemeta'.'site_id' = 8 OR 'wp_sitemeta'.'site_id' = 9 OR 'wp_sitemeta'.'site_id' = 10 OR 'wp_sitemeta'.'site_id' = 11 OR 'wp_sitemeta'.'site_id' = 12 OR 'wp_sitemeta'.'site_id' = 13 OR 'wp_sitemeta'.'site_id' = 14 OR 'wp_sitemeta'.'site_id' = 17) AND ('wp_sitemeta'.'meta_key' = "allowed_themes" OR 'wp_sitemeta'.'meta_key' = "menu_items" OR 'wp_sitemeta'.'meta_key' = "site_admins") ORDER BY 'wp_sitemeta'.'meta_key' ASC LIMIT 0,1000
which will bring up all the necessary values...

everything that looks like this:
a:1:{s:7:\"plugins\";s:1:\"1\";}
should change to this:
a:1:{s:7:"plugins";s:1:"1";}

everything like this:
a:1:{i:0;s:5:\"admin\";}
should look like this:
a:1:{i:0;s:5:"admin";}

ie. remove all the slashes

Save your settings and you should now be able to login at all your sites.

You are the man pumpkinslayer... I was pulling my hair out and this solved my wp-admin redirect problem. I've updated the tags so it might help others as well with older installs.

I can confirm, this was my problem.

I manually deleted the scaping slashes form site_admins in the database and now they are correctly detected again.

My install is in fact really old.