Title: Theme Switcher: warning errors
Last modified: August 18, 2016

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# Theme Switcher: warning errors

 *  Resolved [freefall](https://wordpress.org/support/users/freefall/)
 * (@freefall)
 * [20 years, 5 months ago](https://wordpress.org/support/topic/theme-switcher-warning-errors/)
 * I followed the instructions given by the theme switcher website [http://dev.wp-
   plugins.org/wiki/ThemeSwitcher] and for some reason when I activate this plugin,
   I get errors on the top of my admin pages with the following statement:
 * Warning: Cannot modify header information – headers already sent by (output started
   at /home2/happy/public_html/dearxx/wp-content/plugins/theme-switcher.php:166)
   in /home2/happy/public_html/dearxx/wp-admin/admin.php on line 10
 * Warning: Cannot modify header information – headers already sent by (output started
   at /home2/happy/public_html/dearxx/wp-content/plugins/theme-switcher.php:166)
   in /home2/happy/public_html/dearxx/wp-admin/admin.php on line 11
 * Warning: Cannot modify header information – headers already sent by (output started
   at /home2/happy/public_html/dearxx/wp-content/plugins/theme-switcher.php:166)
   in /home2/happy/public_html/dearxx/wp-admin/admin.php on line 12
 * Warning: Cannot modify header information – headers already sent by (output started
   at /home2/happy/public_html/dearxx/wp-content/plugins/theme-switcher.php:166)
   in /home2/happy/public_html/dearxx/wp-admin/admin.php on line 13
 * I also receive the exact same errors when editing a post.

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

 *  [vkaryl](https://wordpress.org/support/users/vkaryl/)
 * (@vkaryl)
 * [20 years, 5 months ago](https://wordpress.org/support/topic/theme-switcher-warning-errors/#post-305887)
 * This is practically always whitespace either before the opening php tag (<?php)
   or after the closing php tag (?>).
 * Open the theme-switcher.php file in a “plain-vanilla” editor (like notepad2 from
   [http://www.flos-freeware.ch](http://www.flos-freeware.ch)), and setting your
   cursor before the opening tag, hit your backspace key a few times. Then set your
   cursor behind the closing tag and hit the delete key a few times. See if that
   helps….
 *  Thread Starter [freefall](https://wordpress.org/support/users/freefall/)
 * (@freefall)
 * [20 years, 5 months ago](https://wordpress.org/support/topic/theme-switcher-warning-errors/#post-305889)
 * Oh wow, thanks soo much! It was actually the spaces after the closing tag that
   was causing me trouble.
 * Next time I have a problem like that, I’ll check if there are whitespaces before
   and/or after.
 *  [vkaryl](https://wordpress.org/support/users/vkaryl/)
 * (@vkaryl)
 * [20 years, 5 months ago](https://wordpress.org/support/topic/theme-switcher-warning-errors/#post-305893)
 * You’re welcome. Have fun!

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

The topic ‘Theme Switcher: warning errors’ is closed to new replies.

 * In: [Everything else WordPress](https://wordpress.org/support/forum/miscellaneous/)
 * 3 replies
 * 2 participants
 * Last reply from: [vkaryl](https://wordpress.org/support/users/vkaryl/)
 * Last activity: [20 years, 5 months ago](https://wordpress.org/support/topic/theme-switcher-warning-errors/#post-305893)
 * Status: resolved

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