Installed K2 (2.0 prerelease), had some problems with it, uninstalled it and installed the old beta version that didn't work at all, and then I re-installed 2.0 again - but now it does'nt work at all! I can see the dashboard, articles, well everything...but when I publish the K2 Categories menu item, or any one of the other menu items, the page crashes, it's just blank and the html code contains nothing.

please help!

Hi. Yes there was a bug that has already been posted on this forum. If you uninstall the component without uninstalling the K2 system plugins your site will broke. Of course this has been fixed for the final version. In order to restore your site edit the file /plugins/system/k2_joomfish.php and comment out (or remove) the function onAfterInitialise. After that your site should work normally and you should be able to uninstall all plugins of K2 and then reinstall K2.

Tried, but it didn't work. Still get a blank page when I publish K2 categories as a menu item. Any way of cleaning up everything manually, and then reinstall K2?

Hi. A blank page indicates an error. Turn on error reporting on Joomla! and see what's the error you are getting.