Cannot modify header information - headers already sent [#2600802]

Location	http://localhost:81/drupal8/core/install.php/?id=1&langcode=en&op=do_nojs&op=finished&profile=standard&rewrite=ok&rewrite=ok
Referrer	http://localhost:81/drupal8/core/install.php?rewrite=ok&langcode=en&profile=standard&id=1&op=start

Found this error in dblog. It happened at install time.

Warning: Cannot modify header information - headers already sent by (output started at \drupal8\vendor\symfony\http-foundation\Response.php:1249) in Drupal\Core\Session\SessionManager->destroy() (line 267 of \drupal8\core\lib\Drupal\Core\Session\SessionManager.php).

Last log entry before is tour has been installed and the next log entry is classy theme installed.

Comments

Comment #1

25 October 2015 at 10:46

hass created an issue. See original summary.

Comment #2

Ashokjey CreditAttribution: Ashokjey commented 11 March 2016 at 07:53

I am getting the below warning in drupal 8.0.6-dev

Warning: Cannot modify header information - headers already sent by (output started at /var/www/html/ashok/sprint/drupal8/vendor/symfony/http-foundation/Response.php:1151) in Drupal\Core\Session\SessionManager->destroy() (line 267 of /var/www/html/ashok/sprint/drupal8/core/lib/Drupal/Core/Session/SessionManager.php).

Comment #3

11 March 2016 at 07:53

Version:

8.0.0-rc2

» 8.0.x-dev

Core issues are now filed against the dev versions where changes will be made. Document the specific release you are using in your issue comment. More information about choosing a version.

Comment #4

11 March 2016 at 07:53

Version:

8.0.x-dev

» 8.9.x-dev

Drupal 8.8.7 was released on June 3, 2020 and is the final full bugfix release for the Drupal 8.8.x series. Branches prior to 8.8.x are not supported, and Drupal 8.8.x will not receive any further development aside from security fixes. Sites should prepare to update to Drupal 8.9.0 or Drupal 9.0.0 for ongoing support.

Bug reports should be targeted against the 8.9.x-dev branch from now on, and new development or disruptive changes should be targeted against the 9.1.x-dev branch. For more information see the Drupal 8 and 9 minor version schedule and the Allowed changes during the Drupal 8 and 9 release cycles.

Comment #5

pameeela CreditAttribution: pameeela commented 15 October 2020 at 08:00

Status:	Active	» Postponed (maintainer needs more info)
Issue tags:		+Bug Smash Initiative

Thanks for reporting this issue. We rely on issue reports like this one to resolve bugs and improve Drupal core.

As part of the Bug Smash Initiative, we are triaging issues that have not been updated in a long time.

Is this still occurring? I have found some other similar issues and it always appears to be caused by some custom code. If this was a bug in Drupal core at the time it probably was fixed in the meantime, otherwise we'd expect more users to have reported it.