New Install, TM vs 10.6.3 disk

Question

Level 1

7 points

New Install, TM vs 10.6.3 disk

Two nights ago my c2009 Mac Pro (4.1, I think) started acting very wierd--time on the clock was suddenly wrong, it lost contact with our home network, etc, and on restart I got the dreaded grey screen with flashing question mark, alternating with a 'prohibited' icon. It's been doing that ever since and today's the day I need to deal with it.

I have run through all the standard things you should do: reset NVRAM, tried booting into safe mode (it wouldn't), started up from an install disk and ran Disk Repair, which found no problems (twice), started up from and ran Disk Warrior, which repaired the directory but that did not make a difference. I also ran Apple Hardware Test from the Mac Pro's original disks; it found no problems in an extended test. I also have a Tech Tool disk from same time period as the Mac Pro (2009) and Drive Genius 2, however the computer will not boot from either, using either the 'C' key or 'option' key route.

So...looks like I need to try re-installing the system software. I have an original install disk from the computer, also the retail 10.6.3 disk (got it for the family's computers), and I have a complete backup of everything on Time Machine.

Which should I use to restore/reinstall on the HD? I know that if there's a big problem in the system, it is likely there in the TM backup. Is it still best practice to use the disk originally with the computer, where possible? This will mean more updating though, IIRC it's just 10.6.

Thanks for any advice...and any suggestions of other things to try. I am not panicking about the data, though I have four drives in the computer, because of the TM backups. There has to be a solution. BTW I did have a hardware issue with this computer last year, just barely within its Applecare time, something to do with power I think.

Mac Pro, Mac OS X (10.6.8), Also MBP, iPhone 5s lots of Macs...

Posted on Mar 25, 2014 7:39 AM

Reply

Answer 1

ChicagoAl Author

Level 1

7 points

Mar 25, 2014 9:47 AM in response to ChicagoAl

I looked at one other thing just now, the 3V battery on the logic board, which I pulled; it tests good. Also confirmed that last year I had the power supply on this computer replaced, just barely under AppleCare. Though it's a 2009 model I got it in 2010, an Applecare replacement for a previous-generation MacPro with a recurrent problem with USB. Now that I'm looking at the specs, it occurs to me that in July 2010, this model MacPro was either replaced with the 5.1 or just about to be, but oh well. It has worked okay, up to now.

Reply

Answer 2

ChicagoAl Author

Level 1

7 points

Mar 26, 2014 5:39 AM in response to ChicagoAl

Update: I have solved the problem on my own. It seems the regular mavens who used to frequent this board are gone, as 10.6 is quite long in the tooth by now, so if you are looking for a real expert answer to questions here you are not likely to get a reply.

But I'll offer my own very non-expert experience here. For anyone grappling with an issue like this, first of all you must be patient and thorough, and work through things gradually and systematically. What seems like a huge problem may turn out to be something simple, but you can make it much worse by rushing in with the wrong 'fix.'

Fortunately there is lots of information out there, and it is almost certain that any problem you are having with your computer has already turned up elsewhere. Here are a couple of Apple documents that helped me ferret out my issue:

Here's the basic Apple one about the 'flashing question mark' that sometimes appears.

http://support.apple.com/kb/ts1440

This one is a guide to different types of startup using the keyboard, sort of like trying different doors into the computer:

http://support.apple.com/kb/ht1533

As noted above, I'd tried Disk Utility, starting up from an install disk, also had tried Disk Warrior (which can sometimes fix problems), and also Apple Hardware Test, which is usually on the Applications Install disk that comes with Macs, at least up to 10.6. In each case, you insert the disk (hopefully you can) and start up the computer by holding down a certain key or combination of them. While Disk Warrior did a minor repair to my directory, the other two did not find any problems, which was a relief, except for the computer still not starting up!

I finallly started up in 'Verbose Logging' mode, by starting with the 'V' key depressed. I am not any kind of engineer, but I can read, and startup came to a halt with an error message that 'mach_kernel' was missing. That was easy enough to look up on Google, it's part of the OS, a file essential to startup. Meaning, definitely a problem with my OS, not the computer itself.

So I reinstalled 10.6 from the original install disk, which was 10.6.2 I think, then downloaded and installed the 'Combo Updater' to get back to 10.6.8. Current versions of iTunes and iPhoto, and probably some other applications, won't run on any but the latest update. I had to run another Software Update to get the very latest in some programs.

I could have reinstalled from my 10.6.3 retail disk just as easily, I'm sure.

As this problem was confined to the OS, there was no need to use my TM backup, in fact if I'd gone that route I might have restored the computer to a state where it had the same problem.

So, though they seem alarming, the flashing question mark and 'prohibit' icon are not necessarily a huge problem, and you can likely fix it yourself.

Hope this helps anyone who stumbles on this thread!

Reply