Title: update to 3.5.1: Error msg: Cannot modify header information …
Last modified: August 21, 2016

---

# update to 3.5.1: Error msg: Cannot modify header information …

 *  [kmr2013](https://wordpress.org/support/users/kmr2013/)
 * (@kmr2013)
 * [12 years, 12 months ago](https://wordpress.org/support/topic/update-to-351-error-msg-cannot-modify-header-information/)
 * I am a relative beginner at WP & really need help as I appear to now be locked
   out as I get this error message when trying to login into wp-admin and can get
   no further. I dont have the cpanel login details either unfortuntely.
 * Not sure exactly when the problem occurred, but having gone though a standard
   update to the latest version of WordPress (v 3.5.1) I seemed, as a result, to
   get all sorts of things not working that I had not consciously touched. For ex.
   WPML language widget simply disappeared and although I managed to put it back
   I need to change the format. To fix these I was trying to get some code for the
   WPML plugin to work in the functions.php file and now I get this error message:
 * Cannot modify header information – headers already sent by…(output started at/
   homez.386/marcomou/www/wp-content/themes/marcom/functions.php:288) in /homez.
   386/marcomou/www/wp-includes/pluggable.php on line 876 `
    How can I proceed?
 * Site: [http://www.marcomoutsourcing.com](http://www.marcomoutsourcing.com)

Viewing 3 replies - 1 through 3 (of 3 total)

 *  [WPyogi](https://wordpress.org/support/users/wpyogi/)
 * (@wpyogi)
 * [12 years, 12 months ago](https://wordpress.org/support/topic/update-to-351-error-msg-cannot-modify-header-information/#post-3766699)
 * Do you have a back-up copy of the site files? If so, you can use FTP (or other
   file manager) to replace the messed up functions.php file with an older copy.
 * [http://codex.wordpress.org/FTP_Clients](http://codex.wordpress.org/FTP_Clients)
 *  Thread Starter [kmr2013](https://wordpress.org/support/users/kmr2013/)
 * (@kmr2013)
 * [12 years, 12 months ago](https://wordpress.org/support/topic/update-to-351-error-msg-cannot-modify-header-information/#post-3766838)
 * OK thanks that is helpful, but personally no I don’t – I’d have to go to the 
   hoster for it. Also I use MAC so I guess cyberduck would be my option to do this?
   This is a friends site that I was helping out on – ouch, wish I hadn’t touched
   it!
 *  [WPyogi](https://wordpress.org/support/users/wpyogi/)
 * (@wpyogi)
 * [12 years, 12 months ago](https://wordpress.org/support/topic/update-to-351-error-msg-cannot-modify-header-information/#post-3766868)
 * Yes, Cyberduck is fine – though FileZilla has a Mac version as well. I’m assuming(
   from the name) that’s a custom theme – if not, you can download the original 
   theme to your local computer and use the unmodified functions.php file from there.
   You can usually see more info about the theme in the style.css file (there’s 
   generally a commented header section at the top of that file).
 * You can also probably regain access to the site by renaming the theme folder (
   again via FTP) – WordPress will default to the twentytwelve theme (assuming it’s
   in the themes folder) – and allow you to login. But you’ll still need to sort
   out what the problem is in the functions.php file :(.

Viewing 3 replies - 1 through 3 (of 3 total)

The topic ‘update to 3.5.1: Error msg: Cannot modify header information …’ is closed
to new replies.

## Tags

 * [Cannot modify header information](https://wordpress.org/support/topic-tag/cannot-modify-header-information/)

 * In: [Fixing WordPress](https://wordpress.org/support/forum/how-to-and-troubleshooting/)
 * 3 replies
 * 2 participants
 * Last reply from: [WPyogi](https://wordpress.org/support/users/wpyogi/)
 * Last activity: [12 years, 12 months ago](https://wordpress.org/support/topic/update-to-351-error-msg-cannot-modify-header-information/#post-3766868)
 * Status: not resolved

## Topics

### Topics with no replies

### Non-support topics

### Resolved topics

### Unresolved topics

### All topics