166      iPhone_iPad_Mac_apple

imac not recognizing hard drive device

iMac will not recognize my new WD My Passport for Mac external hard drive. 

I have a late 2009 21. 5 inch iMac with Mac OS X Lion version 10.7.5 and I have USB 2.0 ports.  The memory is 4 GB 1067 MHz DDR3.

I made sure that my Finder preference will show hard disks and external disks.  I tried to see if would recognize a DVD and it does.

I was hoping to back up my data to transfer it to a new Mac.

Any help will be appreciated

Hello amfisher ,

Thanks for using the Apple Support Communities!

If I understand correctly, you are unable to see your new external drive from a 2009 iMac.  I will be happy to try to help with this.

In order for your iMac to see it, it may be necessary to reformat the drive. The best format for use with your Mac is OS X Extended (Journaled).  

Format an external hard drive for use with a Mac

1. Connect the drive to a USB port on your Mac.
2. Open Disk Utility.
3. Select your external drive (or one of its partitions) on the left side of the Disk Utility window.
4. Click the Erase tab or Erase button in the toolbar.
5. From the Format pop-up menu, select Mac OS Extended (Journaled). 
6. Type a name for your disk, then click Erase.
7. After the drive is erased, close the Disk Utility window.

This should allow you to copy files to the disk.

Your computer has software on it called Time Machine.  It is fantastic software for backing up your computer.  Information on how to use Time Machine is available here:

Use Time Machine to back up or restore your Mac.

Using Time Machine is generally the best way to move all your files from one Mac to another Mac.

Have a great day!

Thanks for the reply.  When I go to disk utilities I only see what appear to be two hard drives.  The main one is named ST3500418ASQ Media and below that one is Macintosh HD.  I cannot type in the name section for the first hard drive and the Erase Free Space and Erase buttons are shaded.  For the Macintosh HD that name is in the name section.  Only the Erase Free Space button is available while the Erase button is shaded out.  It appears that there is 274 GB available on this HD.  Not sure if I should hit the Erase Free Space button.

Also, when I open Time Machine and hit select disk the only option is "Set Up Other Time Capsule".  When I hit that it opens AirPort Utility which I do not have.  I am guessing that my external HD will not show up until I can get the iMac to recognize the device.

Thanks

Can you post a screenshot of your Disk utility window please. And do not do anything to change your internal hard drive. That is what is listed (I believe). Do NOT use erase free space or anything else right now until we can see a picture of your Disk Utility window.

If your WD drive is plugged in, can you choose "mount" from the disk utility window menu bar?

Aside from anything else, you will need to erase and format the WD drive correctly once your Mac can see it.

Thank you for your response.  I cannot choose "mount" from the disk utility window.

Here is a screenshot of my disk utility:

What you are seeing in your Disk Utility is your internal hard drive. Do not do anything to that - it is fine the way it is. You have the actual hard drive showing with your one volume/partition which contains all your files and which is, by default, always named "Macintosh HD".

There is no external hard drive showing at all; therefore you can't select it.

Do you have another Mac or a friend's Mac (or PC) just to plug your external drive into to see if it is being seen there. I would also contact WD support - I am guessing there is a problem with that external drive.

Thanks.  I plugged it into my son's mac book air and it showed up on his devices.

When I plug it into each of my USB ports the power light does turn on and it does make a faint whirling sound. 

For some reason, your Mac and the drive are not speaking to each other. I'm afraid I don't have a definitive answer for you - since the drive is new, I would contact WD and ask if it is compatible with your older iMac.

If the drive shows up on your son's MBA, can you check to see in that Disk Utility how that drive is formatted? If you can access it, it should show up underneath your son's Macintosh HD. Highlight it (should be something like WD ......) and see if you can format it Mac OS Extended (Journaled) and then under Partition > Options, make sure it is GUID Partition scheme. You should also erase the drive (no need for any of the software on it). If you can do all that using your son's MBA, eject it from there and see if you can now see it when you plug it into your Mac.

...so the only option is to format my drive? What are my options if i have nowhere else to put all of those files?

It would be much better to start your own new thread instead of reviving a dormant one year old thread. Please include info such as device, model/year, OS version, external drive make/model.

Depending on how the external drive is formatted, yes, you may need to format it correctly (if that is what you are asking).

最后更新：2017-08-28 10:17:33

  上一篇： external hard drives

  下一篇： how do I remove trojans from our iMac