By Graham K. Rogers

This week did not get off to a great start when I went into the office and tried to make the iMac I keep there come to life. It had been in sleep mode all weekend. I pressed a key, the screen came on and the spinning wait cursor (that is the official name for the rainbow thing) appeared. Not really a problem usually as the computer has a stretch, looks for the wifi link and wakes up the rest of the system.

The iMac on a Good Day

I left the office, but when I came back about 10 minutes later, the cursor was still spinning and I was wondering what it was waiting for. I gave it a few minutes more and reached for the power button. I hate to do that, but there was no indication that anything was happening there.

The restart was the second indication that all was not well. The startup tone sounded, the Apple logo came on, the gear wheel was spinning. And spinning and spinning and spinning. The iMac now had 95% of my full attention. With the other 5% I was reworking ideas for the afternoon class: a file I wanted in the cloud was not now immediately available.

I restarted the computer again, this time holding down the Command + S keys for a Single User start. When all the text had scrolled over the screen I entered the command fsck -fy at the Unix prompt and a check was under way. One small change was made, so I ran fsck again, this time getting a clean bill of health. We are so easily fooled.

At the end of the Unix session, I typed in reboot and the computer went through the startup process again. This time, after the spinning wheel had been visible for a couple of minutes, the center of the screen showed a No Entry sign. This was getting worse. I tried a Safe start -- holding down the Shift key: No Entry.

There were two options open to me there and then: take the rescue flash drive out of my bag and try Disk Warrior; or use the already-installed tools on the Rescue partition. I chose the latter and restarted (again), this time holding down the Command + R keys. That worked. I was offered the four options of

• Restore from Time Machine Backup
• Reinstall from Mac OS X
• Get Help Online
• Disk Utility

I went for the easiest and selected Disk Utility. The hard disk name was displayed in red in the side panel. I had never seen this before, but had a fairly good idea what it would mean. With no screen shots possible, I took some photographs with the iPhone.

When I highlighted the disk icon, the S.M.A.R.T. status was also in red and the word, Failing was displayed. The computer has been in use since 2007, so the disk has had just over 5 years use: a fair life expectancy for a disk nowadays.

The iMac on a Good Day

When the air-conditioning is not on, the office is hot, so over the course of the couple of years it has been there, the iMac has gone through a range of temperatures: even when the computer off, this will affect some parts. I was also reminded while writing this that as the MacBook Pro is my main working computer, I use the iMac far less these days which may also have had an effect.

With what had gone before, this report of probable failure was not a major surprise. I do not keep a lot of data on this machine, and never backed it up so after I have a new disk installed (if that really is the problem) it will mean rebuilding from scratch and reinstalling several applications. I will be able to do a lot of this directly from my MacBook Pro. That is my day-to-day computer and is fully backed up.

I checked with the technician and was pleased to hear that a visit was planned for the next day by a company that we buy disks from: I later ordered a 500GB replacement.

In the meantime, I walked over to the university Apple retail outlet: the uStore and confirmed that they would indeed be able to replace the disk for me, but suggested I bring my own. Retrieving any data depends on the state of the defective disk.

See also: Hard Disk Failure on the Office iMac: Part 2 - Data Recovery

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.