I run over a dozen WordPress sites on shared hosting with several different hosting companies. But there's one site that I've never been able to update WP automatically; I've always had to do it manually (the site is three years old, so this problem goes back to the days of manual upgrades). I have other sites on the same server that work fine. I'm thinking of completely uninstalling and reinstalling WordPress for that site to get rid of the problem, which I'm quite prepared to do, but if the problem is in the database it will be transfered to the new site when I restore the database.
One thing I noticed is that tmp upgrade files have been piling up in the wp-content directory (not in /upgrades), but deleting them didn't solve the problem. Could that be a clue?
At first I thought the problem occured because the site is in French, but since then I've installed other French sites on the same and different shared hosting accounts, and they update automatically with no problem.
Any insights or things to check would be appreciated. Thanks.