Did a bit of hunting around and came back with this fix – It’s not my own but from ‘gabrielz’.
You have to add the following code:
if ( !defined( 'AUTOSAVE_INTERVAL' ) )
define( 'AUTOSAVE_INTERVAL', 60 );
into admin.php, which resides in the wp-admin > includes folder.
Hope that’s of some use to somebody.
I did bring it up to 2.5.1 the last time I upgraded – but I tried it again on your advice and it gave me the ‘no upgrade required’ screen. So I assume all is well barring that problem.
Did an entire re-install excluding the database and the same thing is still happening unfortunately. 🙁
Had this problem also, upgrading from 2.5 to 2.5.1.
Is it a recognized fault for the developers?
Experimenting with WordPress at the moment for a site launch and did my first upgrade – thought all went well until this issue came up. Glad to see I’m not alone although it is extremely annoying for all involved.