Support » Fixing WordPress » Fatal error Cannot redeclare _wp_post_revision_fields() on upgrade to 3.6

  • Resolved lawbla


    I upgraded to 3.6. I now have the following message:

    Fatal error: Cannot redeclare _wp_post_revision_fields() (previously declared in /home/thedrone/public_html/wp-includes/post.php:4872) in /home/thedrone/public_html/wp-includes/revision.php on line 59

Viewing 13 replies - 1 through 13 (of 13 total)
  • Using ftp try and replace all files and folders except wp-content folder and wp-config,php file from fresh download from here.

    I have got the same, but with a slightly different error!

    Fatal error: Cannot redeclare wp_convert_bytes_to_hr() (previously declared in /home/guusterb/domains/ in /home/guusterb/domains/ on line 1146

    Thanks Govpatel, I will try and replace the files. Should I install the previous Worddpress version just to be sure?


    You will need switch to default theme

    I can’t access the admin of WordPress.. So I can’t do anything. What about you lawbla ? Did you manage to fix it already?

    The only thing I can do is access my ftp and try to follow your instructions and hope it will work again.

    I struggle with FTP so
    i’m having my site administrator restore my site from a backup from last night.
    ill let you know

    Using ftp rename your theme in wp-content/themes folder so that default theme opens.

    Pardon me, I am a bit of a WordPress noob. So, I should rename the folder of the theme I am currently using? What happens? WordPress automatically changes to the default theme? Or should I edit a php somewhere? Thanks for helping me out btw. It’s appreciated a lot!

    I just tried renaming the theme folder. And nothing changed, still the same error.

    John Parris



    I’ve seen others having similar errors in the past during upgrades when a function moved from one file to another during the development process. The best and easiest thing you can do is replace the wp-includes and wp-admin folders with fresh copies, as govpatel suggested.

    Thanks for the tips guys. I tried to replace wp-includes and wp-admin and now the error changed a bit. But that’s the only thing, no response from the admin though.

    Fatal error: Call to undefined function get_post_format_slugs() in /home/guusterb/domains/ on line 1264



    Forum Moderator

    Try re-uploading all files & folders – except the wp-content folder – from a fresh download of WordPress. Make sure that you delete the old copies of files & folder before uploading the new ones.

    Did it! Thanks guys. Just to let you know. I forgot to replace the files that were in the main folder of the new wordpress update. Also I changed the name of the theme folder I was using. After replacing the files it asked me to update and voila, we’re up and running again. Thanks for your help guys!




    Forum Moderator

    Glad we could help 🙂

Viewing 13 replies - 1 through 13 (of 13 total)
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