Q: blue screen after startup and system hangs

I think the work-a-round will be to move a file from  /System/Library/Extensions to someother folder. I need to try this from an external hd to see if this is workable.

Meanwhile,

You may want to post machine info.

blue apple > about this mac > more info button. Click on the hardware line. It has a little triangle in front of the work hardware.

Leave out the serial number.

Example:

Machine Name: iMac

Machine Model: PowerMac4,1

CPU Type: PowerPC 750 (33.11)

Number Of CPUs: 1

CPU Speed: 600 MHz

L2 Cache (per CPU): 256 KB

Memory: 768 MB

Bus Speed: 100 MHz

Boot ROM Version: 4.1.9f1

You could also post info on your video hardware:

Good News. ... If you are brave!

the aty in the message means you have an ATI video chip.  The ATI drivers are in /System/Library/Extensions

Conveniently, the ATI drivers all start with ATI.  I don't know what all the extensions mean.  I have noticed that kext files can be imbedded in kext files.  I'd guess there could be extensions in some of the ATI directories.

I'd try moving all the files/folder beginning with ATI to some other folder & do a normal boot.   

be prepared to do a reinstall if this doesn't work.

Robert

OK, thank you.

Here are my iMac specs:

Hardware Overview:

  Model Name:          iMac G5

  Model Identifier:          PowerMac8,2

  Processor Name:          PowerPC G5  (3.0)

  Processor Speed:          2 GHz

  Number Of CPUs:          1

  L2 Cache (per CPU):          512 KB

  Memory:          1.5 GB

  Bus Speed:          667 MHz

  Boot ROM Version:          5.2.5f1

Video info:

ATI Radeon 9600:

  Chipset Model:          ATY,RV351

  Type:          Display

  Bus:          AGP

  Slot:          AGP

  VRAM (Total):          128 MB

  Vendor:          ATI (0x1002)

  Device ID:          0x4150

  Revision ID:          0x0000

  ROM Revision:          113-xxxxx-117

  Displays:

iMac:

  Resolution:          1680 x 1050

  Depth:          32-Bit Color

  Core Image:          Software

  Main Display:          Yes

  Mirror:          Off

  Online:          Yes

  Quartz Extreme:          Not Supported

  Built-In:          Yes

Display Connector:

  Status:          No Display Connected

Hope that helps.

Thank you

Tim

Success on my test system.  Moved all the ATI files to another folder & did a normal boot.  Got a running system!!!

To try:

1) Make a backup of your files.  You may want to backup your complete system.

2) Create a new folder.  I made /System/Library/ExtensionsDisabled

3) move all the files starting with ATI in folder /System/Library/Extensions to the new folder /System/Library/ExtensionsDisabled

a) goto the Finder   then type

  shift + command + g

b) type in

    /System/Library/Extensions

c) press return

d) This will list the files in the Extensions folder

e) click on the first ATI file

f) hold down the shift key

g) click on the last ATI file

h) drag these files to the new folder

4) do a normal boot.

Notice the current data on these files & folders.

Robert

Great!

Be sure to have backups of your data.  This is a good idea after this scare.  The oher poster said he was running this way since 2005, so happy computering.

Thanks for the report. Glad to hear how you were able to salvage out the use of your Mac. Spent a lot of time sorting out how extensions work. Didn't get all the way to the bottom of how they work, but got far enough.

Robert

ps.

for PPC

tenfourfox

"World's most advanced web browser. Finely tuned for the Power PC."

http://www.floodgap.com/software/tenfourfox/

alternative download site:

http://www.macupdate.com/app/mac/37761/tenfourfox

hey guys, after searching the web for a solution to the same problem - blue screen freeze, safe boot works - for an imac g5 your solution did the job for extending my hope of using the imac longer. i deleted the files in osx 10.5 extensions and logged in with normal boot. simple but yet powerful solution. this was a life saver. hoorayy   

Glad to hear your success.

Robert

I have to say, this post is WAY underpositioned in Google. I'm also surprised this is not listed in ANY of the G5's known common issues lists all over the web (and there are many of these lists). I've been trying to fix this thing forever! After losing all hopes, trying everything and more (and failing once and again) I decided to take my 1.6ghz PPC G5 (Leopard) to Apple service. Thay said it's the logicboard, I couldn't afford a replacement so I took it back. I do not even know how I eneded up reading this post, but it worked so well and it was so easy to accomplish... For the record, I have Nvidia GForce FX 5200 video card: the procedure is exactly the same, I had to move al the extensions beginning with Gforce (DO NOT by any means move the ones beginning with NV as I accidentally almost did!).

Thank you very much everyone specially Mr Robert, you Sr. are a chosen one! greetings from Buenos Aires city, Argentina!

Thanks for your kind comments.

Happy computing.

Robert

It took me three days of struggle before I found this post - thank you!

One question: would getting a new video card solve all of my problems?

What machine do you have?

Query by serial number

"A serial number is a unique, identifying number or group of numbers and letters assigned to an individual piece of hardware or software. It's used for various things depending on the product / brand but what is your Mac's serial number for and more importantly... what is it hiding and what can it do for you ?"

http://www.appleserialnumberinfo.com/Desktop/index.php

or

http://www.chipmunk.nl/klantenservice/applemodel.html

   ( hint by K Shaffer  )

I assume that all the iMac's have the video card attached to the logic board.  Not easily fixed. To fix the video chip you would need to replace the logic board.  Expensive.

Luckily this same problem is on my Power Mac G5 (7,3), so I can easily replace the vid card for about $150 (and upgrade it to 256 from 128 at the same time).

Excellent, thanks for confirming that this works, rccharles, I was working towards this solution myself, but I had only disabled a couple of the ATI drivers so far, not all of them.  My MacBook Pro's card must have developed some bad RAM, but this allows me to boot normally (aside from the screen having an odd cast or tint).  I can't do anything that requires OpenGL, but at least I should be able to get some use out of the computer for the next month or so until I can buy a new Mac (it beats spending $310 for the repair!).

Additional tip: for me, the Extensions and Library folders were locked; I also could not modify them in Single User mode, even though I was root!  The solution was to Safe Boot, and use the Terminal to issue the commands:

sudo mkdir /System/Library/Extensions\ \(Disabled\)

sudo mv /System/Library/Extensions/ATI* /System/Library/Extensions\ \(Disabled\)

I was then able to reboot normally.

Edit: Perhaps the reason this topic doesn't show up as readily in Google as it should is that we haven't used enough of the common search terms that people are plugging into Google!  For one thing, I was freezing on a gray screen, not a blue one, and Apple's Tech Support article that shows up near the top of Google only refers to it as a gray screen as well.

RCCharles .. thanks for the post .. I follow your advice b/c I was experiencing a "bleed through" or greyed out over lay in some areas. I put the extensions into the folder as you directed and it worked after a restart. I am, however, experiencing an issue with a box of greyed out pixels ( I presume) to the right of my mouse arrow ... note the image below:

^'' '' '' '' '' ''

"" " " " " '

"" " " " " '

"" " " " " '

Do you have a suggestion as to how to fix it? the box i made moves around the screen w/my mouse cursor image ... Thanks in advance