By Graham K. Rogers

An update yesterday to an app for the Mac showed a panel that reported a problem with the "Preflight file". The app could not be downloaded.

Later, I found that the update had disappeared, but this morning at home, the update was back in the App Store. When I clicked on it, the "Preflight file" panel appeared and the download failed.

There is a certain perversity about this. At the office, I decided to try one more time. The app appeared and when I clicked on the Update button, it began to download right away, leaving me scratching my head as to why.

I will have to wait for the next update to see if this was a one-off problem or if this will recur. In the meantime, in the noble tradition of shutting stable doors after proverbial horses have bolted, I restarted the Mac (first time in 12 days) more as reassurance than anything.

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.