Wont boot if external hard drive is on

PC wont boot if external hard drive is turned on. If I turn them off boots fine. This has happened since day one.

Hi,
Turn "them off" implies more than one.
You might be experiencing one of three issues or all or them.
1. The external HD needs a firmware upgrade to be compatible with your PC
2. The BIOS boot order is incorrectly set which is typically not the situation with new PCs.
3. The external HD is drawing excessive current from the USB port.
HP DV9700, t9300, Nvidia 8600, 4GB, Crucial C300 128GB SSD
HP Photosmart Premium C309G, HP Photosmart 6520
HP Touchpad, HP Chromebook 11
Custom i7-4770k,Z-87, 8GB, Vertex 3 SSD, Samsung EVO SSD, Corsair HX650,GTX 760
Custom i7-4790k,Z-97, 16GB, Vertex 3 SSD, Plextor M.2 SSD, Samsung EVO SSD, Corsair HX650, GTX 660TI
Windows 7/8 UEFI/Legacy mode, MBR/GPT

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Good day everyone. I know similar questions were raised in this community, but I still have some questions.
I have MacBook Pro(late 2011) with OS X 10.7.5 and external hard drive with Ubuntu 13.04, from wich i can boot succefully on my PC. But MacBook Pro will not boot from my external drive, no matter which key/combination i use during restart.
After googling I found some answers to my initial question, how to boot from external hard drive
https://discussions.apple.com/thread/1852633?start=0&tstart=0
http://www.everymac.com/systems/apple/macbook_pro/faq/macbook-pro-boot-from-exte rnal-firewire-or-usb-drive.html
http://support.apple.com/kb/ht1948
As I understand I need to format my external hard drive into GUID partition type and this will be enough to be able to boot from it on my mac?
With this new partition type, will I be able to install ubuntu again on my external drive?
Does GUID partition type supports NTFS, ext4 and FAT32, linux swap?(I use ntfs for big files, ext4 as partition for ubuntu and fat32, because i use windows, linux and osx)
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here is info on my e-drive

LowLuster wrote:
The only OS that will boot from an external drive is Mac OS X or maybe Linux. For OS X to be installed on any drive it need to be formatted Mac OS Extended and have GUID partition table.
As for Linux I'm not that familiar with it but again for a Mac to boot it need an EFI partition on the drive and I don't think that is possible with NTFS or FAT32 let alone the native Linux format.
Went to wiki to learn more on efi but found artice on uefi.
Operating system loaders are a class of the UEFI applications. As such, they are stored as files on a file system that can be accessed by the firmware, called EFI System partition (ESP). Supported file systems include FAT32, FAT16 and FAT12, and supported partition table scheme is GPT only. UEFI does not rely on a boot sector, although ESP provides space for it as part of the backwards compatibility.[26]
Here is FAQ on official uefi website.
Can UEFI Secure Boot be adopted and implemented by a variety of operating systems?
UEFI specifications are platform-independent, supporting multiple platforms and architectures. In addition, UEFI specifications are designed to promote cross-functionality, as well as to support broad adoption across multiple operating systems, including Windows as well as Linux-based operating systems. The specifications are robust and can potentially complement—or even advance—other distributions, such as Linux-based distributions.
And here is wiki article on GPT expaining OS support.
It is obvious both uefi and GPT are ok with Linux and file systems such as FAT32, ext4 and NTFS.
I guess there is no much difference(or is that the same thing?) between uefi and efi used in Macs.
In your answer to Stark Industries you said that mac can boot linux from external hard drive, well this is not the info i got of official website and it is still my question, because your answer is very inconclusive and your info is partially incorrect

Lion works fine, but it wont recognize my external hard drives. Everything worked with Snow Leopard. Is there a fix?

Lion works fine, but it wont recognize my external hard drives. Everything worked with Snow Leopard. Is there a fix?

What's the URL of the page?
In the mean time clear the cache and reload the page.

Why wont my macbook pro boot with external hard drives connected?

After two years of uninterrupted success running my MBP with five external hard drives attached (two USB, two eSATA with LaCie Expresscard 34, one FireWire 800), my MacBook Pro with Mountain Lion 10.8.2 installed will not boot with the drives attached. Starting up with the option key depressed does not work. Anyone have insight? This didn't happen until I upgraded to 10.8.2, so is there a bug fix needed in that update?

Update, I reset the PRAM (i think) and now the chime is back as I start up... small win but thats all it does.
So I decided to dload a copy of Lion and burn to a disc, then try and boot from there. When i boot holding option and select the dvd it sounds like something is happening, contstant turning or reading of the disk, but nothing is happening on screen, just my old friend the apple logo and his mate the spinning wheel. Starting to concede now, just hoping to get my data back, its mostly photos and some files i cant duplicate.
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Why won't my iMac 27" boot from external hard drive?

I have a new 27in Intel i5 dual core 3.6GHz iMac. It works wonderfully.
My question is this. I have a Pleides Ice Cube external hard drive with a USB 2.0/Firewire enclosure with a 500GB hard drive. I used diskutility to format the hard drive as a GUID Partition Table. I then used SuperDuper to clone the iMac OS 10.6.7 and Apps over to it.
I can select the external drive in System Preferences/Startup Disk to boot from, but when booting the iMac gets as far as the white screen then just stops loading.
I have tried both the USB connection and the Firewire connection (with a Firewire 800 to 400 cable).
I have run Disk Utility and repaired the disk and the preferences.
I have used Disk Warrior to rebuild the directory as well, but the iMac will not boot from the drive.
It does boot from the original DVD's and its own hard drive.
My old 24" iMac had no trouble booting from this hard drive or any of the others I have collected over the years, so I am reluctant to think it is the external drive. It is something to do with this particular processor Snow Leopard and external drives.

It sounds like something in the SuperDuper clone might not have copied well. To get the full answer on that I would check with Apple or SuperDuper to see if they support each other.
As a quick test, if you restart and immediately press and hold "option" on your keyboard do you see your external HD as an option to boot from? If so, click it and see if the boot runs any differently, but if you don't see it at all that could show that the problem is more deep rooted.
Personally, if looking in to either of those didn't give me any other info to go on, I would reformat and start the clone again. BTW, do you know for sure GUID Partition is the format you'd want to do this on? Generally macs use "Mac OS Extended" and some external HDs can use "FAT32" (if you want them to work well with Windows)
Hope that gives a little direction
Alex

Hard drive dead/Boot from external hard drive?

My hard drive failed and I need a new one. For the time being, I'd prefer not to open up my iMac and replace the internal hard drive. I have an external USB hard drive and I cannot install OSX onto this drive (strangely, it takes the first disc but not the second).
Is it possible to boot and run an iMac G5 from an external hard drive? If so, what is required for hardware and what steps need to be taken?
If not, what course of action would you recommend?

It is very easy to boot an iMac from an external drive, but the drive should be a Firewire drive. Get one, then get SuperDuper!, which will enable you to clone your data and system to it. You can then choose the external firewire as your boot drive and operate without any problems.
Apparently, there are ways to boot from a USB drive, but they are complicated and a firewire drive is very straightforward and fast.
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Did 10.4.6 break booting from external hard Drives

Hi
This afternoon, I tried to clone my internal Hard Disk to an external drive. I do the regularly using Disk Utility, and I have not had and problems doing this until today. In fact, when I acquired my Power Mac three weeks ago I cloned my iMac's drive to the same external drive, and then cloned my Power Mac's drive from the external. I did have one hiccup during that last step - I had cloned to the PM's drive while running the PM off the external drive, and the clone was flawed, so I booted using my Tiger DVD and re-cloned the drive using Disk Utility off the DVD. All went well, and my Power Mac's been running flawlessly since.
That was before the 10.4.6 update. Usually, when I have a good known bootable external hard drive, I will only back up my home folder onto the drive. If I've gone through an OS update, or have some major application changes, I will opt to re-clone my internal drive. I did this today.
I tried restarting from the external drive. Yes, I did remember that 10.4.6 did offer that lovely second chime before truly starting up after upgrading, so I waited to see if spotlight was indexing the external drive. I waited 25 minutes. That only thing I saw was the grey apple and - maybe this is a clue - a couple seconds after showing up, that moved an half an inch down screen.
Has anybody been able to clone 10.4.6 to an external hard drive and successfully boot off it? Is my problem of today related to my problem of a couple weeks ago, and I need to run Disk Utility of the Tiger DVD to get a good clone?
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Wish I figured out I was in the mail and address book forum before I posted. Oh Well.
It seems that there might be some sort of weird thing going on between my computer and Disk Utility when booted in the full OS. Earlier, I tried cloning my internal Hard disk using Carbon Copy Cloner, and it worked. My Power Mac boots off the external disk fine and everything runs flawlessly.

IMac won't boot if external hard drive running Time Machine powered on

Upon rebooting, my iMac 3.06 GHz Intel Core 2 Duo with 4GB RAM, running OS X 10.5.4, locked up in a gray screen, the "gray screen of death."
At the recommendation of the Apple Tech Support rep, I turned off the iMac using the power button, and rebooted with my USB and Firewire devices removed.
The iMac boots fine with everything except my G-tech drive 1GB external hard drive running Time Machine with no partitions, attached using a Firewire 800 cable.
If the external hard drive is on, I get the interminable gray screen.
If I boot with the external hard drive powered off and then power it on after I'm at the Mac desktop, the disc image mounts normally on the desktop.
I've already repaired all disc permissions and it doesn't help.
My external hard drive has used 907 of the 931 GB true capacity. Supposedly, Time Machine removes the old files to make room for the new files.
Time Machine itself is running properly once I get my iMac booted in this peculiar way.

Raja,
Do a SMC reset perhaps even a couple of times and see if that helps. Also in System Preferences + Startup Disk make sure the internal HD is selected.
SMC RESET
Shut down the computer.
Unplug the computer's power cord and all peripherals.
Press and hold the power button for 5 seconds.
Release the power button.
Attach the computers power cable.
Press the power button to turn on the computer.
PRAM RESET
Shut down the computer.
Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in step 4.
Turn on the computer.
Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.
Hold the keys down until the computer restarts and you hear the startup sound for the second time.
Release the keys.
Roger

Booting from External Hard Drive (Time Machine)

I just learned that my hard drive is failing. I haven't backed up my data for a while, so I bought a new 1 Terabyte Seagate Drive for Mac. It's one of the new models that don't need a power cord; you just connect it to your computer.
Anyway, a guy at the Genius Bar told me that I can use Time Machine to create a virtual clone on an external drive. I later realized that I might be able to boot up with my external drive and work with my cloned hard drive if my internal hard drive. I've done that with Carbon Copy Cloner before.
Anyway, that's my main question - can one boot up a MacBook Pro on a virtual clone created by Time Machine instead of using the internal hard drive? If so, how do you access it? I think I recall having to hold down a key (Option?) while the computer is booting up, which forces it to give you a choice of hard drives.
One more question: I've backed up some files on my new external drive - about 200 GB in several folders. My internal hard drive is 750 GB, of which about 180 GB is free. In other words, I need about 775 GB space on my external hard drive (570 GB for a virtual clone of my internal drive and 200 GB for the files I've already copied to it. Since it has 1 TB of space, that should be a breeze.
But can I use an external hard drive when it already contains files? In other words, will enabling Time Machine wipe out the files I've already copied to my external drive? Ordinarily, it wouldn't be a problem; I'd simply be replacing some folders with ALL the contents of my internal hard drive, including those same folders. However, I'm a little conerned because my hard drive is failing. I'm just worried that Time Machine might erase the files on my external drive, then poop out before it's finished creating a virtual clone.
So those are my main questions - can I enable Time Machine without wiping out files already copied to an external hard drive, and, once I've copied my entire internal hard drive to the external drive, can I boot up with the external drive and work on it? Thanks.

Hmmmm...I don't know what you mean by "restored," but it sounds like I'm out of luck (my OS X version is 10.7.5). It sounds like I need to purchase another external hard drive and use Carbon Copy Cloner to create a bootable clone on it, right? And could someone remind me how you access multiple hard drives when booting a computer? I remember you have to hold down a particular key(s) while it's booting.
Thanks.

Booting from external hard drive

Hello.
How do I install Mac OS X on an external hard drive, or have Mac OS X running on an external hard drive and boot from it? I tried to install to it and it says Mac OS X cannot be booted from this drive.
What should I do?

Remy,
SuperDuper is another option, but...Note also that USB drives do not allow booting Power PC based Macintoshes under any version of Mac OS X: this is not a SuperDuper! limitation, but one of the OS. If you would like to boot from a backup stored on an external drive, and have a Power PC based Mac, please purchase a Mac compatible FireWire drive.;~)

Macbook wont boot from new hard drive.

I installed a new Western Digital 500GB hard drive into my Macbook Pro (2006 edition). The computer boots up, but it just stays at the screen with the apple and the thing circling underneath it. It won't go any further than that. I have to boot from my external hard drive to get to the Operating System.
Also it won't shut down nor restart unless I hold down the power button.
I installed Snow Leopard 10.6 on the new hard drive. The longest I waited was like 10 minutes. Should also note that there is a CD stuck in my CD/DVD optical drive (I used an external drive to install snow leopard)...I don't know if that's interfering. It didn't interfere with my old hard drive.
I've also used Disk Utility. It says the disk needs repairing, so I repair it, and it says successfully repaired, but I can't shut down or restart the computer, so I have to shut it down by holding the power button. When I turn it back on, it says it needs repairing again. Maybe it's not saving because of the improper shut down?
Please help

Welcome to Apple Discussions!
Did you format the new drive before trying to install the OS?
http://discussions.apple.com/thread.jspa?threadID=1885474&tstart=60
Try that, and if still no joy, you might have a defective drive. If so, WD will replace it under warranty.
Good luck!

Cannot boot when external hard drive is connected.

Hello everyone!
I got a brand new Macbook Pro w/ Retina 13" for Christmas today, and I've ran into an issue. I have a Samsung external hard drive with my documents and photographs on (and nothing else), and if I start up my mac with it plugged in, my computer hangs on the black screen (no Apple logo). If I leave it for 5 minutes, it eventually works. Also, shutdown is very slow as well. I've tried booting without it plugged in, and it works perfectly. I've ran the disk utility on it, and it reports no problem.
My hard drive's format is in ExFAT (previous Windows 7 user).
Booting in verbose mode doesn't work either, as no text shows up.
Could someone please tell me how to boot my mac quickly without having to disconnect the external hard drive every time?
Thanks.

KaiSilverthorne wrote:
Hi CellarDwellr,
My Samsung HDD uses power from the Mac (and I didn't have the mac plugged in when tried). I am going to reformat my external HDD to see if that helps (it's in ExFAT), as I need to in order to use it for Time Machine backups.
I'll let you know if anything works.
Thanks,
Kai
I see. Well, yeah, in order to use it with Time Machine, format it to Mac os Extended (Journaled)

G5 won't boot from external hard drive

I have installed Leopard on my external hard drive, but have not gone through the 'setup'. I want to boot my G5 from the hd now, but when I restart holding down the option key, the internal hard drive is the only option that appears. When I do boot from the internal hd, the external hd is recognised perfectly and I can see all the files and everything - I just can't seem to boot from it. The newer iMac I used to install Leopard on the external hd will boot from it, but the G5 refuses to recognise it in the boot options.
Any help much appreciated.

No. If you boot an installer disc on an Intel Mac it will only install an Intel version of OS X. You would need to boot the installer disc on the G5 then install OS X onto your external drive. However, if you do that you will not be able to boot the Intel Mac with the external drive. The only solution to using one external drive on both computers is to partition the drive. Install OS X on one partition using the G5, and install OS X on the other partition using the Intel Mac.

Boot from external hard drive

I have just loaded Leopard 10.5 wonderful but not overwhelming. It deleted OS 9 and now ALL my cool classic games won't run. I have a eMac G4...Can I add an external hard drive..load OS9 on it and boot and run my games???

Bill W wrote:
If your eMac was capable of booting directly into OS9 before,
I suspect that any eMac which could boot OS 9 would have to be 800 or 700 MHz units, and therefore will have problems installing Leopard. (Min speed: 867 MHz, and the installer checks.)
then yes you can install it on an external drive (firewire), assuming the OS9 installer sees the external drive. I think you might also be able to reload OS9 onto your internal drive without partitioning. If that doesn't work, another option is to partition the internal drive and install 9 on a separate partition.
The OS 9 System Folder may still be around. (I don't know, I haven't installed Leopard yet.) However, Classic is dead and gone on Leopard.
His best bet would be to get an external drive, install a pre Leopard version of OS X (and Classic) on it, and reboot from that drive when he wants to run Classic. I have already set up an external drive to do just that in the event that I need to run Classic on my iMac. My eMac will simply stay at Tiger.

Wont boot if external hard drive is on

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