I’ve been plagued with this problem for several weeks now. See my post about it here.
I even asked my hosting provider to downgrade my wordpress back to 2.5 because i didn’t have this problem when i was using it then.
But after searching again (using a different search term), i found the solution.
From gabrielz :
I have discovered a way to not have the problem.
For some reason, the lines above of wp-admin\includes\admin.php where deleted on new version:
if ( !defined( ‘AUTOSAVE_INTERVAL’ ) )
define( ‘AUTOSAVE_INTERVAL’, 60 );
I just put it again (and in my case I changed the parameter value to 120s) and now it is working fine.
I now have my normal blogging life back.. hahahha