Cannot modify header info error

Hi LovegroveShop,

It can be related to a compatibility conflict. Could you try to disable all your plugins except WooCommerce and WPML plugins and check if the Warnings still persist? If not, try to enable your plugins again, one by one, and check which is the one that brings the warnings up. We’ll work to make it compatible. ??

Thanks,
Bernat

Thanks for the quick reply. I’ve deactivated all other plugins and get the same error. ??

I’ve also tried switching from Twenty Fifteen theme to Twenty Fourteen theme. Both themes are out-the-box uncustomised.

Deactivating any WPML plugins removes the error but then your plugin won’t work. ??

Many thanks for your help.

Hi LovegroveShop,

In this case I think the best will be to check your site configuration directly. Could you please open a new ticket in our wpml.org support forum? This way we’ll be able to ask you for private data and check your site to help you in a better way. ??

Thanks,
Bernat

It appears the error message has now disappeared. : /

I can’t say for certain what I did. I carried on regardless whilst waiting for a response. I’ve re-activated all the plugins added new plugins and configured a few more WPML settings.

Can I now be certain the error isn’t there anymore if it’s not displaying in the admin area?

Many thanks for your help. Much appreciated. ??

Hi LovegroveShop,

Well, I can’t guarantee you as I’m still not sure what was the issue… It can be related to some plugin activation or mis-configuration… So in that case, yes, a new activation can fix the issue definitely But anyway, I’d suggest you to keep an eye on this to be sure that it doesn’t happen again. If it gets back, please let us know.

Thanks,
Bernat

Hi Bernattorras,

I’ve the same error when i’m log in to wp-admin (just see this error once a day).

Warning: Cannot modify header information – headers already sent by (output started at /wp-content/plugins/woocommerce-multilingual/inc/multi-currency.class.php:902) in wp-includes/option.php on line 749

I deactivated each plugin except wpml but the error doesn’t disappear…
I take a look in the code in option.php it’s a setcookie function at this line and in multi-currency.class.php it’s the multi-currency drop down menu (who doesn’t work by the way).

WP V4.1.1
woocommerce ML v3.5.1
WPML ML CMS v3.1.8.4
WPML String Translation v2.0.14
WPML Translation Management v1.9.9
WPML Media v2.1.8

Thanks,

Yohann

I check in the error_log and i’ve got many errors connected to multi-currency like this one :

[21-Feb-2015 00:24:11 UTC] Erreur de la base de données WordPress You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ‘) AND meta_key=’_wcml_custom_prices_status” at line 1 pour la requête SELECT post_id, meta_value FROM wp_postmeta WHERE post_id IN() AND meta_key=’_wcml_custom_prices_status’ faite par require(‘wp-blog-header.php’), require_once(‘wp-includes/template-loader.php’), include(‘/themes/liselondonv2/taxonomy-product_cat.php’), wc_get_template, include(‘/themes/liselondonv2/woocommerce/archive-product.php’), wc_get_template_part, load_template, require(‘/themes/liselondonv2/woocommerce/content-product.php’), post_class, get_post_class, apply_filters(‘post_class’), call_user_func_array, wc_product_post_class, WC_Product->is_on_sale, WC_Product->get_sale_price, WC_Product->__get, get_post_meta, get_metadata, apply_filters(‘get_post_metadata’), call_user_func_array, WCML_Multi_Currency_Support->product_price_filter, WCML_Multi_Currency_Support->get_product_custom_prices

Is it connected?

Yohann

I seems that some of the errors are coming from your theme, does this issue persist on a default theme like twenty-fourteen?

If the issue persists with the default theme and all non WPML plugins deactivated I suggest that you open a ticket on WPML.org so that we may take a close look at the issue.

Hi Robert,

Changing the theme doesn’t resolve my problem. I open a ticket on WPML

Thank’s

To those who are saying this could be related to a plugin … that doesn’t look like the case.

I’ve got a brand new installation of WP – no plugins, just one page created – and I get these errors:

Warning: Cannot modify header information – headers already sent by (output started at path on my server /wp-admin/includes/plugin-install.php:83) in path on my server /wp-includes/option.php on line 748

and

Warning: Cannot modify header information – headers already sent by (output started at path on my server /wp-admin/includes/plugin-install.php:83) in path on my server /wp-includes/option.php on line 749

I did enable one of the “bundled themes” but I believe I was getting that error even before enabling that theme (which theme I can’t seem to now get rid of but that’s a different thread!)

No matter what theme I choose I’m getting the above error messages whenever I click on Plugins>Add new in the control panel.