In order to access the files on your Mac you will usually need to have a functioning version of OS X, along with a working display so you can interact with your system. From here, you can either use file sharing on the local network to access your data, or copy your data to external drives. However, if your Mac will not boot, or its display is not working properly, then you still may be able to get your data off of it.
The solution here is to have another Mac handy, and then start the faulty one in Target Disk Mode. This mode starts the system to a basic hardware level that in essence turns your Mac into an external hard drive. From here, you can use a Firewire or Thunderbolt cable to connect your system to another to access your data:
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Ensure the faulty Mac is turned off.
- Attach your Mac to another one using a Thunderbolt or Firewire cable.
- Start up your Mac while holding the T key.
Special boot modes on Macs require the system capture the keys being pressed before the firmware passes control to the operating system. This window of opportunity is immediately when the system’s boot chimes sound, which is also when the controllers for bluetooth keyboards are activated. This means that for wireless keyboards, you may have trouble activating Target Disk Mode as you will have to press and hold the T key immediately when the boot chimes sound, as opposed to before. Therefore, if you are having trouble getting your system into Target Disk mode, then try using a USB keyboard and holding the T key from the point you power on your Mac.
If your Mac is still not able to get into Target Disk mode, then you either have a firmware password set on your system to in part lock out special boot modes, or your Mac is experiencing enough faults that Target Disk mode cannot be accessed. In these cases, you will need to take your Mac in for servicing.
If your Mac is able to get into Target Disk mode, then it will show up on the second Mac as an external hard drive, and only require you supply a password if FileVault encryption was enabled on the faulty Mac. Once the drive is unlocked and mounted, you should have full and unrestricted access to all files on it.
Also Target Disk Mode with USB.
I’ve noticed that my iMac will sometimes not recognize special boot modes from the Apple wireless keyboard. This appears to be, in some cases, because the keyboard is asleep and not sending a signal to the computer. To deal with this I press the power button on the keyboard just after starting up the iMac and before the boot chime sounds. If the light on the keyboard is green when the chime sounds the computer will usually recognize it. Of course, I also have a wired keyboard available if that doesn’t work for some reason.
Besides using another Mac to boot an unresponsive system in Target Disk Mode, a viable system on an external drive can work as well. It depends on why the Mac won’t boot. If it’s a software problem then booting from an external drive will usually work. If it’s a hardware problem that won’t respond to any bootable volume, then Target Disk mode is the next option. If that does not work, the internal drive will have to be removed from the computer by a qualified technician. If you can get the computer to boot from an external drive or mount in Target Disk Mode, I suggest the first thing to do is run Disk Utility on the problem drive, checking the drive and repairing permissions. If you have a capable third-party maintenance tool like DiskWarrior and/or TechTool Pro, you can use either of those to further test and repair the drive. Then try to boot the computer once more. There are many reasons a system can become unresponsive. Not all of them are fatal. Another option is too use the external boot drive or computer to download and reinstall the latest OS X combo update. This will replace many system files, some of which may be the source of the problem.
Of course the best way to protect your files from a system or hardware failure is to have and maintain a complete backup of the system and your files. A Time Machine backup will do in some cases – if you can boot in the Recovery HD partition or mount the drive from an external source. A clone is even better in many instances because you can boot up immediately from there and try to repair the internal drive. And, if your computer is not usable in any of the suggested scenarios, you can use your clone with another Mac to get your work done while the failed computer is in the shop for repairs. For what it’s worth, I use both Time Machine for incremental backups and Carbon Copy Cloner to maintain a clone. I’ve had occasion to use and bless them both.
A few days ago, I had the error message that I had to clear my hard drive to start iOS. I chose not to because I had nothing backed up on another drive and very little saved to other sources. I have the boot camp system that allows me to run windows on my Mac and run the two in parallel. I tried to start windows, but it is also saying there is a problem that cannot be fixed inhibiting the start of the system. is there a solution to this?