Mac will not boot when external drives are connected [OS X Lion]

[temple_treefrog]

Hi Guys,

Need your expert help here please...

Ever since I upgraded to OS X Lion, my iMac will not boot unless I disconnect all three external hard drives.

Specs:

• iMac "27 2009 model with latest build of OS X Lion
  
• 3x External hard drives (2x USB connected directly / without USB hub, 1x Firewire 400)
  
• No boot-camp partition installed
  

Troubleshooting steps so far:

• Performed a Verify Disk with Disk Utility: no issues found
  
• Checked the start-up disk pane in preferences to ensure the start-up disk is selected
  
• Checked permissions and executed maintenance scripts with OnyX: no issues found
  
• Reconnected external hard-drives to different USB ports: did not fix issue'
  

This only started happening ever since I upgraded to OS X Lion. I occasionally have system freezes and there are times when the Mac will not wake up from sleep.

I rarely use my iMac (mainly because I'm never home), always takecare of housekeeping such as checking disk permissions and have little applications and crap installed.

What could I do to fix this?

Also has anyone else experienced any issues similar to this?

[Nick H. Supervisor]

When you say that your iMac doesn't boot up, can you be a bit more specific? I mean, are you saying that you push the power button and nothing happens at all, or does it start to do something and then provide some sort of message - perhaps about how it can't find an operating system on the disk?

[Shaun N.]

Try some of these options, I'd suggest holding the options key D to force it to boot into the first internal drive rather than looking at your other drives.

http://face.centospr...s-boot-options/

[temple_treefrog]

When you say that your iMac doesn't boot up, can you be a bit more specific? I mean, are you saying that you push the power button and nothing happens at all, or does it start to do something and then provide some sort of message - perhaps about how it can't find an operating system on the disk?

Thanks -- to be more specific, I mean:

White screen appears, grey Apple logo appears, spinning circle appears underneath Apple logo... However the log-in screen (username and password dialog) does not show. The Mac stays static on the white screen with the Apple logo. If I remove all of the external hard drives and restart, it boots up as normal.

[Nick H. Supervisor]

White screen appears, grey Apple logo appears, spinning circle appears underneath Apple logo... However the log-in screen (username and password dialog) does not show. The Mac stays static on the white screen with the Apple logo. If I remove all of the external hard drives and restart, it boots up as normal.

I can't quite remember right now because I don't have my mac in front of me to test it, but from the sounds of it what the computer is doing is recognising that there are multiple hard drives, and it is trying to check each drive to see if any of them hold an operating system. How big is each external drive? I would imagine that if you left them plugged in and tried booting up, you would get that screen and then eventually it would continue to boot in to Lion.

[Shaun N.]

Or we could do what I suggested?

[Pam14160]

This . . .+Shaun.

or, just disconnect the drives, load up then reconnect. That's what I do (sorry Shaun the CTL "D" doesn't work with mine). I have been doing this since Leopard, so it not just a Lion problem.

[Nick H. Supervisor]

On the off-chance that Shaun's instruction doesn't work (I'm not saying it won't work, but as Pam14160 pointed out it doesn't work for them), just hold the option key [ ? ] when you first push the power button. The computer will display all connected drives, and you then just select the main hard drive and it will load that.

[Shaun N.]

sorry Shaun the CTL "D" doesn't work with mine

Option is not control. The option key looks like what Intrinsica said "[ ? ]" If you are using a non Apple keyboard then it would be your windows key

[Shaun N.]

Have you got your start up correct? Go into settings and start up disk and select your main internal one that you want to boot from. Try rebooting then.

Edit: I see you have already tried this.

[temple_treefrog]

How big is each external drive? I would imagine that if you left them plugged in and tried booting up, you would get that screen and then eventually it would continue to boot in to Lion.

Both USB hard drives are 2TB each and the Firewire hard drive is 1.5TB. Before anyone suggests that amount of storage is excessive, all three drives are almost full.

Try some of these options, I'd suggest holding the options key D to force it to boot into the first internal drive rather than looking at your other drives.

http://face.centospr...s-boot-options/

Attempted this a few times, did not work. :(

Have you got your start up correct? Go into settings and start up disk and select your main internal one that you want to boot from. Try rebooting then.

Edit: I see you have already tried this.

Yep already tried, thanks for checking though.

[PurpleHaze420]

I've had this happen to me recently and I also narrowed it down to connected USB devices, in my case, not my 2Tb external HD but a connected empty USB stick that was interfering with the boot process.

For easability i've just disconnect it until I actually want to use it while in an OS.

[CPressland]

Try booting it in verbose boot mode and let us know what step the boot is hanging at. CMD+V or just hold V at boot I believe.