Dreaded blinking question mark - only sometimes

[darrenleomiller]

About once a month I have a problem where the machine won't boot and I get the blinking question mark icon on the screen. I've read lots (and lots) of posts about this, all which say that the hard drive is dead or something similar. Disk Utility and Drive Warrior sometimes see no disk and sometimes see a disk that reports a 0 byte capacity. The thing is, it has always come back. The typical pattern is that nothing I do seems to help. Eventually I've tried all the standard things (safe mode, pram reset, etc), rebooted it a bunch and then walk away for a few hours. Nothing seems to work immediately, but if I leave it alone it comes back. What gives?

In case it matters I've got an iMac 20" (?), intel duo 2.8 GHz with a 500 GB WD drive.

I used to think the problem might be heat related, but I recently had to leave the machine off for a week in this state and when I returned the problem persisted. So it isn't *just* heat.

Thanks,

Darren

 

[FourCandles]

One way or another, it would seem to me that the hard drive is failing. They can often produce intermittent problems before failing completely.

First thing I'd do is to back up all of your data while you still can. Buy/beg/borrow an external hard drive and use Carbon Copy Cloner or Super Duper to back everything up.

Have you actually been able to repair/verify the disk with Disk Utility? Any errors?

You suspect heat problems - is this based on sensor readings?

 

[darrenleomiller]

Fortunately I've got a good backup system, so I'm not deeply worried about losing stuff, just time and the drive itself.

When the drive is acting up nothing seems to be able to do much with it. When it is behaving everything tests out just fine. It is pretty baffling.

The suspicions around heat are mostly superstition at this point, but partially based on the fact that just leaving it off (and unplugged, which I didn't mention earlier) seems to be involved in making it better. This is post hoc ergo propter hoc, though, so I'm not really conviced either. The symptoms don't point to anything physically wrong with the drive itself, but I'm planning to replace it nonetheless. I just figured I'd throw this out to the world before doing so, in case someone came back and said "yeah, believe it or not this happens when the machine is too close to the printer" or something silly like that.

 

[andreiru]

My SSD does the same. I believe it's something to do with either the SATA cable or the graphics chip on the motherboard being incompatible with 3Gbit connections / SSDs. I've downgraded the EFI to half the speed otherwise I get total system freezes.

The only way out of this in my experience is to keep trying rebooting it up to 15 times or booting it off of an external enclosure.