I've been at this for hours and I'm on the verge of wiping out the site and starting from scratch, WITHOUT the K2 plugin. I've been reading forums all day, tons of people are having the same issue but no real solution could be found. I've done everything from changing languages to clearing the cache, to looking into code.

I woke up this morning and was unable to access any items or categories in the backend.

Any help would be greatly appreciated.

PHP Built On Linux boscustweb0905.eigbox.net 3.2.52 #1 SMP Tue May 20 13:39:02 EDT 2014 x86_64
Database Version 5.5.32-log
Database Collation utf8_general_ci
PHP Version 5.3.13
Web Server Apache/2
WebServer to PHP Interface cgi-fcgi
Joomla! Version Joomla! 2.5.20 Stable [ Ember ] 30-April-2014 14:00 GMT
Joomla! Platform Version Joomla Platform 11.4.0 Stable [ Brian Kernighan ] 03-Jan-2012 00:00 GMT
User Agent Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_5) AppleWebKit/537.74.9 (KHTML, like Gecko) Version/6.1.2 Safari/537.74.9

Hi. The information you provided is inadequate. Clarify what's going on. You say you cannot access items or categories. Are you getting a message from Joomla! A meesage from the browser? A blank screen? An empty list ? Also try to enable Joomla! debugger to see any SQL errors.