XF 1.4 Fatal Error: Class 'XenForo_CacheRebuilder_Forum' not found

I've XF v1.4.6 with elastic search. Since 2 weeks all of a sudden I have one of these every 2 or 3 days:

ErrorException: Fatal Error: Class 'XenForo_CacheRebuilder_Forum' not found -library/XenForo/CacheRebuilder/Abstract.php:114
#0 [internal function]: XenForo_Application::handleFatalError()
#1 {main}

array(3) {
["url"] => string(34) "http://xyz.com/forum/deferred.php"
["_GET"] => array(0) {
["_POST"] => array(4) {
["_xfRequestUri"] => string(51) "/forum/index.php?threads/unknown.374321/page-712"
["_xfNoRedirect"] => string(1) "1"
["_xfToken"] => string(8) "********"
["_xfResponseType"] => string(4) "json"
"XenForo_CacheRebuilder_Forum" sounds vital, what is this?


XenForo developer
Staff member
It's something that has not been part of XenForo since 1.1. Unfortunately PHP's fatal error messages don't give any useful details, but this is something that would have been triggered by an add-on.
ah, OK, I guess it's " [WMTech] - User Self Delete LITE" which I installed around that time. it has this somewhere in the code:
$rebuilt = XenForo_CacheRebuilder_Abstract::getCacheRebuilder('Forum')->rebuild();