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XF 1.4 Error in Server Error Logs

Hi - i'm getting the following error about one every 1-2 days in the xF Server Error Logs:
ErrorException: Fatal Error: Class 'XenForo_CacheRebuilder_Forum' not found - library/XenForo/CacheRebuilder/Abstract.php:114
Any ideas what is causing it and how to resolve?


XenForo moderator
Staff member
Have you recently upgraded or done any work on the server?
The error suggests there may be missing file(s) or corruption.

Run a file health check in the ACP.
Download a new upgrade .zip and upload the files to your server.


XenForo developer
Staff member
Unfortunately, as PHP doesn't give a backtrace for fatal errors, it's hard to get more specific information. I've just searched the code for references to the function that is triggering your error and there's no way for it to be called via deferred.php by default. (It's actually only around to reduce backwards compatibility issues with add-ons originally built for 1.0/1.1.)

As such, I can only guess this is related to an add-on. Unfortunately, it's hard to figure out which one. It appears to be attempting to rebuild forum information. Any idea what this would be based on the add-ons you have installed?