Cannot login or access dashboard after WP update to 4.4

I can confirm that wp-admin has 755 permissions, exists. So does login.php, plugins.php, etc… All of which are throwing 404 errors.

This issue is not just on one site. We have over 15 WP sites that have been upgraded to 4.4 with this problem. The only one I’ve found that still works is the one that has not been upgraded yet :/

Hey James,

To avoid confusions:
1. Our 4 installs are in the root; I also see that others are having problems with installs in subdirectories /subdomains.

2. All plugins were de-activated prior to update.
3. Cloudflare was de-activated prior to update.
4. Cleared all caches (browsers, databases, etc.) prior to update.
5. Double-checked .htaccess… => nothing suspicious.
6. Double-checked wp-config … => nothing suspicious.

But upgrade failed: cannot login and access dashboard anymore.
Rolling back to previous version => everything back to normal.

Any idea, patch?

It sounds like it might not be limited to sub directory installs. We need to identify the common thread that might lead to the bug.

Is there any unique configuration or setting that is common between your sites?

Perhaps a hosting environment or set up issue?

Are there plugins that are common between all of your installs? (This send less likely the issue, because we’ve all tired deactivating plugins without avail, but perhaps if a caching or similar plugin changed a setting permanently)?

I’ve tried to revert our WP back to 4.3 to fix the issue but it’s still not allowing us to login :/
The particular site I’m trying to get back into is a newer install and here are a list of the plugins being used (which I’ve disabled). The sites that have not been updated are on the same dedicated server and we can login to.

– hide-youtube-related-videos
– gravity forms
– mgi-tubelab
– wp-fastest-cache
– all-in-one-we-security-and-firewall
– superbly-menu
– Ultimate_VC_Addons
– duplicate-post
– js_composer
– LayerSlider
– elated-cpt

I don’t know if this will help but here is the first error I’m getting in my error_log report:

[12-Dec-2015 00:41:59 UTC] WordPress database error Can’t create/write to file ‘/tmp/#sql_bc6_0.MYI’ (Errcode: 28) for query SHOW FULL COLUMNS FROM sw_options made by require(‘wp-blog-header.php’), require_once(‘wp-load.php’), require_once(‘wp-config.php’), require_once(‘wp-settings.php’), include_once(‘/plugins/testimonials-widget/testimonials-widget.php’), tw_requirements_check, get_transient, delete_option

Hmm… the only common plugin I have on my setup with yours is gravity forms, and I doubt that would cause this issue – which leads to me thinking it’s a WP Core issue.

When I made the update, I did it on a local development environment and used git to commit the changes and then merged those changes into the staging site on a remote server. Now, that’s the site with the issue.

I’ve even reverted the merge, even, and switched branches – which, unless there is a separate issue with the git tracking, implies that the update either made a database change that is causing the 404 error, or did something to the server configuration?

Joshua I also tried to restore one of the site’s db backup and reverted back to WP 4.0 and still can’t login. I did notice that all the sites are giving the error:

WordPress database error: [Can’t create/write to file ‘/tmp/#sql_bc6_0.MYI’ (Errcode: 28)]

hmm… is that a server error log or are you seeing that on the page? my results are 404 pages, no debug_log output, but I haven’t check other server logs

Yes that’s a server error log. My results are giving a 404 error on WP but I thought maybe checking the server log might help some…

Yea, great, that might be a clue. I’m going to try replacing the codebase and the DB on a previous version, I haven’t touched the database yet. I’ll report back, though it might be later this evening or tomorrow.

Joshua I just had our server team look into this issue and they’ve fixed the issue which has resolved the login issue. I’m waiting to hear back from them what might have caused this. Now I’m looking into what after we’ve updated to 4.4 it won’t let us upgrade any plugins previously installed.

Yea, I’d love to know what they did to fix the login/dashboard 404 issue. My hosting support couldn’t track down any obvious server issues.

I’ll keep you posted Joshua. They haven’t responded back yet but once I do I’ll be sure to ask what they did to fix it and hopefully the issue won’t resurface.

If there’s no traction from a developer by Monday, I’ll make sure one of them takes a look.