How to fix "Cannot send headers; headers already sent" error in magento version 1.9.3.3?

[Ashish_k_php]

a:5:{i:0;s:147:"Cannot send headers; headers already sent in /home/abc/public_html/app/code/core/Mage/Catalog/Model/Category/Attribute/Backend/Image.php, line 1";i:1;s:1783:"#0 /home/waterc/public_html/lib/Zend/Controller/Response/Abstract.php(115): Zend_Controller_Response_Abstract->canSendHeaders(true)

 How to fix this error in Magento ver: 1.9.3.3?

If you have any idea please help me to fix this issue.

Thanks

[Tom Robertshaw]

This is normally caused by a space/letter before an opening <?php bracket. Would you be able to check the edits that you've made since before you received this problem?

https://stackoverflow.com/a/8028987/1960680

[Ashish_k_php]

@Tom Robertshaw thanks for reply

Already follow that link and remove space but then after getting 404 Page not found the error.

[Tom Robertshaw]

That sounds like a different problem. Can you share more on that one?

[Ashish_k_php]

Yes, Header issue is solved. @Tom Robertshaw thank you.

Now if we removed Magento Cache then after loading any page of the project then 1st-time display 404 Page not found the page, after that if we again reload that page then page load properly with all content.

If you have any idea about this please reply.

[Tom Robertshaw]

I've not come across that problem. That sounds like a strange one. I'd probably try and trace through the code and see where the 404 is triggering and why. It is a Magento 404 or a web server 404?