iMac fails to boot up

Tonight my iMac failed to boot up.

It eventually reached the two shades of blue, but no further. I tried the holding down the alt key thing and then selected the Mac HD - same result of course.

I did the same with the Boot Camp partition and XP didn't start either.

I tried again with all external disks disconnected - same result.

I booted up to the Install CD and repaired the disk. It said the disk was OK.

I tried Repairing permissions - it found errors, which it said were fixed.

However, it still would not boot up.

So I booted to the Install Disk and did the repair system reinstall (not sure of the correct name - the one that doesn't erase everything). This has been successful and now it boots up. Not tried the Bootcamp one again yet. Now backing up with Time Machine and SuperDuper! before I risk anything else.


I know it is too late now, but what is likely to have been wrong, what might have caused it and what should I have done to fix it please?


Lastly, which files can I now delete - i.e. which ones did it replace or repair? About 21GB I think, so where can I find them please?

These may be the early signs of a failing hard drive. I would certainly keep your backup and not erase it... and continue making regular backups (this is a good idea anyway). I would also consider replacing the hard drive - just to be safe.

You can use a SMART analysis tool to read the diagnostics contained on your hard drive. These tools are available free on the Internet. A quick Google search will come up with several.

This is the important part: when looking at the results from the SMART tool, you want to look at the value for the "Reallocated Sectors." If it is anything more than 5 (and some people say even 1), then there is a definite possibility that the drive is on its way out. Even though hard drive manufactures may not call a hard drive bad until it has more reallocated sectors, and the tool officially says "OK", reallocated sectors are still not a good sign.

Keep a close eye on your system, and if you start seeing crashing, or extended periods of the spinning beach ball, it may be time to replace the drive, reinstall the OS and restore from a backup.

Jeff

I tested it with a SMART utility - it seems some of the sectors are faulty


So a couple of examples of computers:

1. Last week my neighbour had a problem with her computer. It is a Dell, about 5 or 6 years old. The hard drive has failed. So £40 or so for a new hard drive, a couple of hours to reinstall and copy back the data and they are as good as new.


2. Two years ago I bought an iMac. This cost several times what she paid for her old Dell. Already the hard disk is faulty. Unfortunately of course, the iMac is a sealed unit, so I have a £900 doorstop with a cheap and shoddy hard drive.


I can't afford to waste over a thousand pounds on a new iMac (however tempting they look) every two years when I can upgrade every component in a PC when required - for half the cost.

Sadly, it seems I am on my way back to Windows7. A real shame as the Mac is far superior - until it wears out

What kind of iMac is it? You could crack the machine and install a new HD. Another option is to install a new OS on an external HD and use that as your boot drive and you will have your iMac back - without the internal drive perhaps.

I think if you have an Intel machine then a USB external can be a startup drive and if not an Intel (PPC) the external must be a firewire drive.

Last option is take it and have the internal drive replaced by a service shop.

Here is a link to one of very many videos.

24" iMac Hard Drive Upgrade

That looks rather risky. Maybe once the drive actually fails I might give it a try. I tried upgrading the memory in a Netbook - which recognised the memory increase but has not worked properly since

Just a thought - I use SuperDuper! as well as TimeMachine (different external disks). Would it help at all to reformat and reinstall the internal disk and then copy back from the SuperDuper! backups, or is the disk failing physically?

Two years seems way too soon for a physical failure - especially as it is a Seagate. I have Seagates I have had for far longer than that, without any sign of failure.

Nighthawk4 said:

That looks rather risky. Maybe once the drive actually fails I might give it a try. I tried upgrading the memory in a Netbook - which recognised the memory increase but has not worked properly since

Just a thought - I use SuperDuper! as well as TimeMachine (different external disks). Would it help at all to reformat and reinstall the internal disk and then copy back from the SuperDuper! backups, or is the disk failing physically?

Two years seems way too soon for a physical failure - especially as it is a Seagate. I have Seagates I have had for far longer than that, without any sign of failure.

Click to expand...

You can try the reformat and reinstall, and a hard drive should last a lot longer, however, it is not at all uncommon for them to die after 2yrs.

24" IMAC 3.06 GHz intermittent boot issue

I switched to the IMAC in December 2008 short after purchasing Vista for my PC. The IMAC has been brilliant up until four weeks ago.

The MAC froze four weeks ago and when it was rebooted it came up with a grey folder and question mark.

The PRAM was reset, and a further reboot attempted without any joy. The disk utility was then used to check the HD however it was not available?

After unplugging the IMAC for 20 minutes it booted up successfully.

During the last four weeks this has continued, sometimes last a few days before it freezes or fails to boot up following a shut down, and sometime only a day. Generally if it is left unplugged for a period of time it seems to rectify itself.

Is this a sign that the HD is on its way out, or is there something else I can check?

Thanks
Nick

It's always better to replace a hard disk than to trash a perfectly good computer because of a dead disk.

... Although I've gotten my fair share of second-hand Macs because of idiot friends who decided they were "dead" because of some minor issue.

rybold said:

I switched to the IMAC in December 2008 short after purchasing Vista for my PC. The IMAC has been brilliant up until four weeks ago.

The MAC froze four weeks ago and when it was rebooted it came up with a grey folder and question mark.

The PRAM was reset, and a further reboot attempted without any joy. The disk utility was then used to check the HD however it was not available?

After unplugging the IMAC for 20 minutes it booted up successfully.

During the last four weeks this has continued, sometimes last a few days before it freezes or fails to boot up following a shut down, and sometime only a day. Generally if it is left unplugged for a period of time it seems to rectify itself.

Is this a sign that the HD is on its way out, or is there something else I can check?

Thanks
Nick

Click to expand...

I have been searching web to find someone with similar problem and you have described word for word what is happening to my late 2008 iMac.
It occurs after computer locks up with spinning ball of death. Eventually I have to switch off as it won't force quit anything. It then can't find internal hard disk to boot. If I use SuperDuper back up on external firewire disk I can get computer up and running but then no sign of internal disk anywhere. Only solution I have found is to unplug, walk away and try a couple of hours later. Most of the time this solves it. I have unplugged all attached cables ( USB and firewire ) when trying to boot up but this nevers solves it.

Any clues ? As when hard disk re-appears and is checked with disk utility it gives the ok verdict.

I am running Snow Leopard with all updates in place.