Title: Error displayed during automatic plugin upgrade
Last modified: August 19, 2016

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# Error displayed during automatic plugin upgrade

 *  [Scott Bressler](https://wordpress.org/support/users/sbressler/)
 * (@sbressler)
 * [16 years, 2 months ago](https://wordpress.org/support/topic/error-displayed-during-automatic-plugin-upgrade/)
 * I’ve seen similar errors to mine around the forum and Internet, but no solution
   to my particular problem: When I upgrade plugins using the admin interface, I
   get this error (some details changed for privacy):
    `Warning: Cannot modify header
   information - headers already sent by (output started at /nfs/c05/h03/mnt/707XX/
   domains/mydomain.com/html/wp-admin/admin-header.php:18) in /nfs/c05/h03/mnt/707XX/
   domains/mydomain.com/html/wp-includes/pluggable.php on line 868`
 * Most people have said that there is an end php tag missing in some file, but 
   the two files referenced are core files that I haven’t modified. This happens
   after deactivating the old plugin and before removing the old plugin. Any ideas?

Viewing 4 replies - 1 through 4 (of 4 total)

 *  [esmi](https://wordpress.org/support/users/esmi/)
 * (@esmi)
 * [16 years, 2 months ago](https://wordpress.org/support/topic/error-displayed-during-automatic-plugin-upgrade/#post-1453392)
 * [Solving “headers already sent” warnings](http://codex.wordpress.org/FAQ_Troubleshooting#How_do_I_solve_the_Headers_already_sent_warning_problem.3F)
 *  Thread Starter [Scott Bressler](https://wordpress.org/support/users/sbressler/)
 * (@sbressler)
 * [16 years, 2 months ago](https://wordpress.org/support/topic/error-displayed-during-automatic-plugin-upgrade/#post-1453411)
 * Thanks, esmi. As I said in my original message, however, I had tried doing what
   other people suggested, as on that page, with this error, albeit to no avail.
 * Just to check, I downloaded a fresh copy of WP MU and diff’ed admin-header.php
   with the currently installed copy and there were no changes. Line 17, as you 
   can see [here](http://svn.automattic.com/wordpress-mu/tags/2.9.2/wp-admin/admin-header.php),
   is where HTML output starts from that page (intentionally!) – this is not a simple
   PHP-end-closing-mark missing. Or if it is, it’s not from admin-header.php. Any
   other thoughts?
 *  [masonjames](https://wordpress.org/support/users/masonjames/)
 * (@masonjames)
 * [15 years, 10 months ago](https://wordpress.org/support/topic/error-displayed-during-automatic-plugin-upgrade/#post-1453614)
 * Any update on this? I have a wpmu 2.9.2 install that’s throwing up the same error
   on automatic plugin upgrades (the upgrade does complete correctly though).
 *  [TexInWien](https://wordpress.org/support/users/texinwien/)
 * (@texinwien)
 * [15 years, 10 months ago](https://wordpress.org/support/topic/error-displayed-during-automatic-plugin-upgrade/#post-1453616)
 * +1
 * I have the problem on wpmu 2.9.2, as well. I have the exact same error as sbressler(
   directories are different, of course, but line numbers and files are the exact
   same) and the exact same behavior as masonjames.
 * Would be nice to find a solution.

Viewing 4 replies - 1 through 4 (of 4 total)

The topic ‘Error displayed during automatic plugin upgrade’ is closed to new replies.

## Tags

 * [automatic upgrade](https://wordpress.org/support/topic-tag/automatic-upgrade/)
 * [headers](https://wordpress.org/support/topic-tag/headers/)
 * [php](https://wordpress.org/support/topic-tag/php/)

 * In: [Fixing WordPress](https://wordpress.org/support/forum/how-to-and-troubleshooting/)
 * 4 replies
 * 4 participants
 * Last reply from: [TexInWien](https://wordpress.org/support/users/texinwien/)
 * Last activity: [15 years, 10 months ago](https://wordpress.org/support/topic/error-displayed-during-automatic-plugin-upgrade/#post-1453616)
 * Status: not resolved

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