Our contributor Ralf Meier in Washington received an email from Apple advising him that the 1TB Seagate disk in his May/July iMac 27in could need replacing. Since I have a similar machine, I phoned Apple to ask if I need a new disk. They referred me to this site which anyone can use to check their computer. So I did, and mine doesn’t need attention. Reason? It has a Western Digital drive which, of course, I should have checked before phoning Apple. Before visiting the Apple support site it’s a good idea to check About This Mac and note the make of the disk.