13 Replies Latest reply: Jul 30, 2012 4:21 PM by Neil Coppin
rockstone555 Level 1 Level 1

Guys, need some help here, I have been struggling with this problem for weeks. Worked with Apple Care, Apple service center. but the problem came back again. Now I just want to reinstall the system by my self.


HW info:  IMAC  21.5 inch , CPU Intel i5, RAM 4G, Graphic Card, AMD 6700M

System info: Lion 10.7.2, Win 7 home edition, Bootcamp 3.2 (probably), Got 4 logic Hard disk, (1 MAC, 1 BootCamp 2 NTFS windows disks)


Issue history: Worked fine in both Lion and Win 7. One day in Win7, display got distorted and system hang. Reboot the iMAC, can't get in MAC, recovery HD or safe mode of MAC (Holding shift key when boot up). Ended up in a white screen. Can get in the Win7, but can only work on defaule VGA graphic card driver, if install the AMD 6700 driver, system gets hang sooner or later.


Trouble shooting steps:

Tried following steps, all ended up in a white screen:

1. reboot holding shift key to safe mode

2. Reboot holding command+option+R to recovery mode

3. Reboot holding option goes to recovery HD.

4, Get a Lion installation DVD from internet, hold "C" during reboot.

5. Unplug the power cord for several hours and reboot again.

Tried resetting PRAM (hold command+option+P+R) but no help.

Sent the iMAC to Apple support center, the engineer there tied to reset the PRAM again and they secussefully get in the MAC, they tested the hardware and everything seems fine.  But issue happened again two days later.


I am trying to reinstall Lion by myself, but I can't get in to the installation page till now, neither for the recovery mode. Any suggestion to get this done? Thank you so much for your help.

iMac, Mac OS X (10.7.2)
  • BGreg Level 6 Level 6

    To get into Lion recovery mode, you reboot holding the command and R keys down ... not sure what command, option, R does (although apparently not much).  You should also be able to go to the App store and download Lion from there.

  • rockstone555 Level 1 Level 1

    Thanks for replying Greg, it is not working for the Recovery mode... I tried the command + R key and I can't even see the globe. Booting from recovery HD is the same.

  • ds store Level 7 Level 7

    Ok, I think the engineers used a wired keyboard and you didn't so try that and the PRAM reset.


    If you get in you need to backup your data off the drive completely out of all partitions.


    Are all four of these partitions of yours (OSX, bootcamp and two NTFS) on the same boot drive?


    Apple only supports one Bootcamp partition on the boot drive now, having the two NTFS + the likely installed NTFS software on the OS X side is likely the cause of your problems.



    Only use NTFS for Windows in Bootcamp, that's it.


    Use exFAT with a MBR on external drives for everything else and Win/Mac compatibility.


    I suspect you had this 4 partition scheme before on 10.6 and then upgraded to 10.7.



    Also installing drivers into Windows? The Bootcamp is supposed to set all that up, the video drivers for Mac hardware are not public.


    Your treating your Mac like it's a generic PC hardware and it's not, despite the fact the processors are the same.




    Once you get all your data, hold c boot off the 10.6, yes the 10.6 disk and use Disk Utility to Erase with Security option > Zero the ENTIRE drive (far left makers name and size) and reinstall 10.6 and then same user name, update to 10.6.8, install Lion cakes, and then remake Bootcamp, reinstall Windows and your programs and files (only) from backup.


    You only get one more partition on the Lion boot drive, that's it.


    No geek schemes like on Windows where you partition files etc., separately.


    After you do the Zero Erase + Reinstall of everything, I suspect your problems will disappear.



    Into the Lion cage with you!



  • rockstone555 Level 1 Level 1

    thanks ds. I suspect the problem is on the bootcamp partition. I went to the verbose mode during startup, found everytime the startup process stuck with a white screen when accessing bootcamp partition. No matter I am booting the MAC or the bootable DVD.  Now, I can only in the single user mode and can't run the disk utility. I searched the command like pdisk, fdisk etc. to delete the bootcamp partition but none of them worked. I believe once I cleared the partition, it will at least allow me to reinstall the system. Any idea how to do that?

  • rkaufmann87 Level 9 Level 9



    Are you using a wireless keyboard? If so do NOT hold down any keys when restarting or cold booting until you hear the startup tone. Once you hear the startup tone hold down the Option key and you will see the Recovery volume as well as your internal HD and I also believe your Windows 7 volume.

  • rockstone555 Level 1 Level 1

    Yes, that's what I did, I heared the startup tone then press the key. I am sure the PRAM is cleared coz I got a immediate reboot after I press command + option +p +r.   I think I narrow down the problem to the bootcamp partition problem as each time the start up process hangs there. Any idea on how to erase the partition in single user mode? I can only get into SMU and Windows. I ran pdisk and found it is not showing correctly information

  • rkaufmann87 Level 9 Level 9

    Sorry I don't do MS Windows.

  • Yuengdog1983 Level 1 Level 1

    If you are tyring to use disk utility but can only us Single user mode look at the "fsck" section of the KB article http://support.apple.com/kb/TS1417

  • rockstone555 Level 1 Level 1

    thanks! will give it a try after work...

  • rockstone555 Level 1 Level 1

    appreciate your reply , BTW, if I use windows USB keyboard, is it going to work? which key is "command"? the 'Win' key?

  • rathokan Level 1 Level 1

    I'm having the same/similar problem.  My iMac hangs on boot, either into Lion or Recovery HD.  Before this happened, Lion was crashing on flash video playback.  I ran the Apple Hardware Test and everything checks out (both standard and extended test).


    I can sometimes boot into Lion after running the Hardware Test, but the machine crashes again shortly and remains unbootable.  One symptom seems to be a flashing/flickering screen.   If Lion crashes after successful boot, I can still access files on the HD via my TiVo, AirVideo server, etc... even though the computer is unresponsive.


    Tried booting off an external HD and I get a kernel panic


    Booted into Firewire Target mode and am able to access the HD


    Am able to boot off the original system CD and get to the installer, disk utility, etc...


    Any ideas out there?  Is it good that I can successfully boot off the original system CDs?  Does that mean my logic board is OK?



    iMac 24" 3.6 C2D, GeForce 8800 GT 512MB, 4GB RAM, Lion 7.4 (I believe), no Windows partition/bootcamp

  • rockstone555 Level 1 Level 1

    Hey rathokan, my IMAC turned out to be a hardware problem on both Hard Drive and Video Card .... I got both of them replaced by apple care and it is working fine now. I ran the hardware test on my computer in before and it was showing all good, but it was indeed the hardware issue.

  • Neil Coppin Level 1 Level 1

    Hi Rathokan,


    Were you able to get to the bottom of your problem? I have identical issues!