Fatal error: Call to undefined function wp_cache_get() in wp-includes/option.php

– If the troubleshooting steps you mentioned failed to resolve the issue, try manually re-uploading all files and folders EXCEPT the wp-config.php file and the /wp-content/ directory from a fresh download of WordPress. Make sure that you delete the old copies of files & folder before uploading the new ones. Read the Manual Update directions first!
– BTW, always backup everything (including your database) before doing any actions, just in case.

Hi, thanks for the reply, I did a manual update, it didn’t help unfortunately.

Any other suggestions?

Have you tried switching to the unedited default, core-bundled Theme (such as Twenty Twelve, Twenty Thirteen or Twenty Fourteen) for a moment using the WP dashboard to rule out any theme-specific issue. If you don’t have access to your admin area, you can switch to the default theme by renaming your current theme’s folder in wp-content/themes and adding “-old” to the end of the folder name using via FTP or SFTP or whatever file management application your host provides. Alternately, you can remove other themes except the default theme. That will force your site to use it.

Hi Tara,

Thanks for the help but I solved it myself already!

I renamed db-error-php (to backup-db-error.php) in the wp-content folder and that pointed me to the solution as now the error red: “error establishing database connection”. I was working on this site, moving hosting package, and had not filled in the database details in wp-config.php correctly.

Once I had filled in the details the site was running normally again!

(I thought that db-error.php was a file from the w3 total cache plugin, that’s why I renamed it).

Glad you got it sorted ??