Fatal error: Call to undefined function wp_install

Question

In Wordpress i can get this error message while update into wordpress4.4 how to reset my website

Fatal error: Call to undefined function wp_installing() in /home/u365143419/public_html/keerthikaprinters/wp-includes/functions.php on line 1354

Answer 1

The function wp_installing is a new function in /wp-includes/load.php, as of WordPress v4.4.0.

From my research/experience, there are 2 reasons for the problem (and it could be both):

1) Corrupted WordPress files, for example caused by an incomplete update installation, in which case you need to reupload (eg. via FTP) the core WordPress files (ie. /wp-admin/, /wp-includes/, and the .php files in the root of your WordPress site (although be careful with wp-config.php if you have a dev environment version too!)). At the very least check that /wp-includes/load.php includes the new function definition for function wp_installing().

2) WordPress becomes "confused" by an update installation (for example by a failed update), thinking that it is in the installation process, when it is not (or when it failed partway).

After making sure that 1) was not the problem (by doing a file comparison between the 'out of the box' WordPress files (from the WordPress zip download), doing a bit more research, and pulling my hair out), I found that there is a WordPress PHP flag WP_INSTALLING that the core uses during an update as part of handling the installation process. At my wits end I temporarily put the following in wp-config.php:

define('WP_INSTALLING', false);

and reloaded my failed/broken site, and lo and behold, my WordPress site started working! I then remove this line, and the site has been working fine since.

I can only assume that because my first attempt to update WordPress using the automatic WordPress update feature failed, and that when I then FTP'd up all the WordPress core files in attempt to do a manual update to fix it, that WordPress was somehow confused as to what state it was in (which even restarting the web server didn't fix). Forcing the WP_INSTALLING flag temporarily to false thus got WordPress sorted out internally, and allowed things to operate normally again. Interestingly after doing this, WordPress prompted me to update my database (which I did), and which seems to me to confirm that the WordPress update installation got interrupted midway and was the cause of my problems/this fatal error/WordPress thinking that the WP_INSTALLING flag was actually currently set as true.

Answer 2

Here's what helped me to fix the problem:

1) create a backup of all files and the database (highly suggest)

2) Delete all files and folders except for the folder wp-content. You will need this folder. It contains all the files for your theme and plugin.

3) Replace all the wordpress files in the install download EXCEPT for wp-content.

4) Update wp-config.php with your database credentials. They can be retrieved in your current wp-config.php.

5) Test your website. If all seems well login into your admin panel and see if the database needs updated.

Hope it helps, if you didn't already solve the problem.