With the recent security vulnerability announcement about WordPress <= 2.8.3 and the subsequent availability of a WordPress upgrade, I’ve taken to upgrading all of my WordPress blogs. On a few of them, the auto upgrade feature didn’t work.
While researching a solution, I stumbled across a site that had some info on how to fix it. The solution presented on the site said to go into the wp-content directory and delete the directory named “upgrade”. I tried this and my auto upgrade still failed. As I continued looking for a fix, I found another site with a comment on the page that mentioned changing the memory settings for the running PHP process. I did that and my problem was solved.