PHP Fatal error: Call to undefined function WP_Filesystem() [closed]

The error is in custom-functions.php line 529 where you might be using file system function outside of admin, you can fix this by including the core admin file.php file like this.

require_once(ABSPATH . 'wp-admin/includes/file.php');

Related Posts:

  1. WordPress displays 500 error on PHP errors
  2. How to fix empty dashboard issue in WordPress?
  3. Fatal error: Call to undefined function wp() in ../wp-blog-header.php?
  4. Call to undefined function nocache_headers() [closed]
  5. The famous WordPress white screen of death
  6. How do I “fix” a wp-blog-header.php error message?
  7. Blank/White Screen on Frontend but Accessible backend?
  8. PHP Fatal error: Cannot call overloaded function for non-object in wp-includes/capabilities.php [closed]
  9. current_user_can on WordPress 3.1.1
  10. WordPress White Page with Certain Database
  11. Memory issues – Fatal error: out of memory – plugins?
  12. What does this mean: Object of class WP_Error could not be converted to string
  13. How to customize the critical error message?
  14. 500 Error only one one page in the WP admin
  15. How to make my plugin code die gracefully
  16. Fatal error…Please help me
  17. Fatal error after updating to WordPress 5
  18. Revslider error. Impossible to enter admin dashboard [closed]
  19. Fatal error after update [closed]
  20. White screen of death after an auto update of WordPress
  21. Fatal Error after migrating WordPress site from one host to another
  22. WordPress problem with fatal error
  23. After Plugin deinstallation, Login impossible and line50 error
  24. Need help decrypting error and warning messages
  25. WordPress crashed during update
  26. There has been a critical error on your website – won’t fix no matter what
  27. Fatal error: Cannot redeclare get_header_image() (previously declared in [closed]
  28. locked out of wordpress site ‘warning: require once’
  29. Can’t access my site due to fatal error [closed]
  30. White screen after a couple hours?
  31. My site is not working because of this: Fatal error: Cannot redeclare be_themes_contact_authentication [closed]
  32. Fatal error: Uncaught Error: Call to undefined function do_action_ref_array() when using wp_signon function
  33. Allowed memory size exhausted
  34. Fatal error: Call to undefined function the_archive_title ()
  35. Fatal error: Call to undefined function reset_mbstring_encoding
  36. WP_Error with get_category_parents
  37. Fatal Error Class ‘WP_Widget_Pages’ not found in /home/****/public_html/wp-includes/class-wp-widget-factory.php
  38. Fatal error in wordpress htdocs
  39. failed to open stream – wp-includes/blocks/file.php
  40. WordPress critical error (tried plugin + debug!)
  41. Not able to access admin console after Installing and activating a plugin
  42. Fatal error: Uncaught Error: Class ‘WP_REST_Meta_Fields’ not found in
  43. Uncaught Stripe\Exception\SignatureVerificationException: Unable to extract timestamp and signatures from header
  44. unable to edit any page of my wordpress website
  45. How to remove theme that caused WordPress to crash?
  46. Fatal error: Uncaught Error: Call to undefined function twentynineteen_post_thumbnail()
  47. Php Fatal error. Blank wordpress admin panel
  48. Recoverable fatal error: Object of class WP_Error could not be converted to string in /home/xyz/mysite.com/wp-includes/formatting.php on line 3796
  49. How to fix wordpress white screen of death a cause bad php code?
  50. Catchable fatal error: Object of class WP_Error could not be converted to string in
  51. WordPress site suddenly stopped working
  52. 500 Internal Errors
  53. wp search-replace inside site’s directory bring PHP fatal error
  54. WordPress Fatal Error
  55. Blank page and 301 redirect
  56. White Screen of Death error
  57. WSOD on 4.1.1 after migrating from Bluehost to Dreamhost
  58. Object of class WP_Post could not be converted to string
  59. Fatal error: Call to undefined function term_exists()
  60. Call to undefined function is_blog_installed(), after creating functions.php [closed]
  61. Parse error: syntax error, unexpected T_FUNCTION on plugins page
  62. Blank screen at login/logout – tried everything!
  63. Fatal error: Can’t use method return value in write context
  64. Fatal error: Call to undefined function request_filesystem_credentials()
  65. Fatal error: Allowed memory size of 94371840 bytes exhausted (tried to allocate 42240 bytes) in /home/dh_w7t9sk/morleywines.com/wp-content/plugins/
  66. HELP! Fatal Error? I can’t access the Dashboard. How do I regain access? [closed]
  67. Flamingo’s Fatal error: Allowed memory size of 134217728 … wp-includes/wp-db.php on line 2516 [closed]
  68. Fatal error: Uncaught Error: Call to undefined function wpcf7
  69. How to fix Fatal Error in wp-includes/meta.php after upgrade to PHP 8
  70. Call to undefined function create_function()
  71. Fatal error: Uncaught Error: Call to undefined method Elementor\Utils::is_ajax() [closed]
  72. “CRITICAL Object of class WP_Error could not be converted to string” using templates with twig
  73. WordPress core files – PHP Warning: file_exists(): open_basedir restriction in effect
  74. PHP Notice: Undefined offset: 1 with array when reading data
  75. Weird PHP error: ‘Can’t use function return value in write context’
  76. A fatal error has been detected by the Java Runtime Environment. EXCEPTION_ACCESS_VIOLATION
  77. Error Logs to Diagnose Error 500 in LAMP
  78. Can I delete plugin files using FTP?
  79. Fatal Error relating to sessions.php
  80. Theme Javascript.php Overwritten Nightly [closed]
  81. I can´t access my admin panel. I tried all possible solutions
  82. Call to undefined function add_menu_page() on theme activation
  83. How can I understand what is the cause of WP death (white screen)?
  84. Fatal error: Call to a member function get_page_permastruct() on a non-object
  85. Getting HTTP error 500 after migrating a website
  86. Error: Call to a member function get_error_code() on a non-object
  87. 5 PHP Fatal error: Uncaught ArgumentCountError (Cannot Find)
  88. Fatal errors to undefined function in theme 404.php file [closed]
  89. wordpress admin part is not accesbile after server shifting
  90. Bug in wp_insert_post script and form, probably something simple I am not seeing
  91. WordPress Core is causing 500 internal server error
  92. WP_Fatal_Error_Handler OR WP_Error OR try/catch
  93. Fatal error: Class ‘RDTheme’ not found
  94. WordPress error on my website
  95. Blank sign in page
  96. WP white screen of death after duping a site that works fine on same server
  97. After being hacked Fatal error: Call to undefined function get_header() in 404.php on line 1
  98. Fatal error trace not shown in development setup
  99. Saving metabox updates causing fatal error
  100. Internal server error when enabling Multisite in WordPress