By Graham K. Rogers

One of my morning rituals after breakfast and email is to check for updates. I start with the iTunes App Store as that usually has a few, then I try the Mac App Store. Apart from a beta update which I am trying to ignore, there was a download of AutoDesk's 123 Design shown this morning.

When I pressed the Update button, a panel appeared showing that the update could not be completed as the "Preflight file" had not been signed by Apple.

I remembered that this had happened before, most notably in June last year and a solution was suggested on Many Tricks that had me changing preferences in Keychain Access from "Require if Certificate indicates" to "Best Attempt". Unfortunately, that was not the solution and I am stuck with a file that won't (for now) download.

Graham K. Rogers teaches at the Faculty of Engineering, Mahidol University in Thailand. He wrote in the Bangkok Post, Database supplement on IT subjects. For the last seven years of Database he wrote a column on Apple and Macs. He is now continuing that in the Bangkok Post supplement, Life.