XF 1.4 Upgrade Errors

I've just upgraded two sites to XenForo 1.4 and the first worked without issue...

The second brings up the following errors on the main forum list:

Server Error
Invalid model 'XenForo_Model_Category' specified

  1. XenForo_Model::create() in XenForo/NodeHandler/Category.php at line 61
  2. XenForo_NodeHandler_Category->_getCategoryModel() in XenForo/NodeHandler/Category.php at line 27
  3. XenForo_NodeHandler_Category->isNodeViewable() in XenForo/Model/Node.php at line 544
  4. XenForo_Model_Node->getViewableNodesFromNodeList() in XenForo/Model/Node.php at line 772
  5. XenForo_Model_Node->getNodeListDisplayData() in XenForo/Model/Node.php at line 745
  6. XenForo_Model_Node->getNodeDataForListDisplay() in XenForo/ControllerPublic/Forum.php at line 81
  7. XenForo_ControllerPublic_Forum->actionIndex() in XenForo/FrontController.php at line 347
  8. XenForo_FrontController->dispatch() in XenForo/FrontController.php at line 134
  9. XenForo_FrontController->run() in /home/sites/apexracinguk.com/public_html/forums/index.php at line 13

I've removed all the plugins and tried to swap the template back to normal (as this is different on both sites) however still no luck.

Any ideas?
Also got the following after managing to find my thread to post a status update to users:

rrorException: Fatal Error: Class 'XenForo_DiscussionMessage_Definition_Post' not found - library/XenForo/DataWriter/DiscussionMessage/Post.php:25
Generated By: Darren, A moment ago
Stack Trace
#0 [internal function]: XenForo_Application::handleFatalError()
#1 {main}
Request State
array(3) {
["url"] => string(65) "http://apexracinguk.com/forums/threads/forum-outage.912/add-reply"
["_GET"] => array(0) {
["_POST"] => array(9) {
["message_html"] => string(195) "<p>OK, the main page list is dodgy so I've raised a support ticket and disabled all add-ins temp.</p><p><br></p><p>Pity, as the first site worked a treat!</p><p><br></p><p>Bear with me.&nbsp;</p>"
["_xfRelativeResolver"] => string(56) "http://apexracinguk.com/forums/threads/forum-outage.912/"
["attachment_hash"] => string(32) "5ba7a2e57bfdb49de9a39192fd0d6c26"
["last_date"] => string(10) "1410362235"
["last_known_date"] => string(10) "1410362235"
["_xfToken"] => string(8) "********"
["_xfRequestUri"] => string(33) "/forums/threads/forum-outage.912/"
["_xfNoRedirect"] => string(1) "1"
["_xfResponseType"] => string(4) "json"


XenForo developer
Staff member
These would both indicate that the files haven't been uploaded properly. You can check this with the file health check, but you should re-upload them.
Hi Mike,

Seems you are correct - I walked away during the upload process and I've just spotted that 18 files were not uploaded correctly.

Thanks once again for your support - great as always!

I'll reupload these now and see how it goes!