Title: Upgrade Problems
Last modified: August 19, 2016

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# Upgrade Problems

 *  [truwizard](https://wordpress.org/support/users/truwizard/)
 * (@truwizard)
 * [15 years, 8 months ago](https://wordpress.org/support/topic/upgrade-problems-19/)
 * My site [http://wizardspost.com/](http://wizardspost.com/) is WORKING but a strange
   problem has appeared.
    I was UPGRADING to wordpress latest version when it stalled(
   I think) On refreshing it gave the following messages:
 * Warning: call_user_func_array() [function.call-user-func-array]: First argument
   is expected to be a valid callback, ‘__return_zero’ was given in /home/wizard/
   public_html/wordpress/wp-includes/plugin.php on line 166
 * Fatal error: Call to undefined function is_multisite() in /home/wizard/public_html/
   wordpress/wp-login.php on line 85
 * Now I cannot login to my wp-admin.
    Can anyone suggest what I should do. ——-
 * I went to public_html and tried changing Plugins folder in wp-includes. That 
   made it give an additional error and the website too stopped opening.
    So, I 
   restored the original and at least the site started opening again but my problem
   of not being able to log in for dashboard
 * Please could you TRY OUT [http://wizardspost.com/wordpress/wp-login](http://wizardspost.com/wordpress/wp-login)
   to know

The topic ‘Upgrade Problems’ is closed to new replies.

 * In: [Installing WordPress](https://wordpress.org/support/forum/installation/)
 * 0 replies
 * 1 participant
 * Last reply from: [truwizard](https://wordpress.org/support/users/truwizard/)
 * Last activity: [15 years, 8 months ago](https://wordpress.org/support/topic/upgrade-problems-19/)
 * Status: not resolved

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