mac does not see external hard drive

You can set up Time Machine to back up external drives. The setting is a bit "counter-intuitive."

In System Preferences Time Machine pane, there is a button for Options. When you click that, you get a panel that shows a list of disks that are being excluded from backup. By default, all external drive volumes are excluded from backup. The only disk (volume) that is included for backup (by default) is your internal drive volume (your primary startup disk "Macintosh HD"). So, to include your external drive in Time Machine's backup, you remove its disk from the list of excluded disks.

Of course, if you include your external drive in Time Machine's backup, the other external drive that is being used for Time Machine's archive needs to be big enough.

You can also add to the exclusion list (by clicking the plus sign at the bottom of the list). For example, if you don't care if your Downloads folder gets backed up, you can add that folder to your list of excluded items. Then, your startup disk still gets backed up, but your the Downloads folder is excluded.

Oh no

Bought another case and exactly the same scenario...so it must be the Hard Drive now?

That makes it more likely that the hard drive itself is faulty.

You have a new case, so you can buy a new hard drive for it separately and install it. That's what I do myself, so that I can get the hard drive that I want for a good price, and put it into a high-quality case that I purchased empty. Newegg.com is a good place to look for bare hard drives, at good prices. Be sure to look for the same type of hard drive.

Attached another hard drive to usb. Same happens.

Also i pod and i pad does not show up

So frustrating

Hopefully, you did rule out a problem with the USB port way back when I replied to your post on December 19th? I said you should shut down the Mac, disconnect all USB devices, and then confirm the USB port was working properly (with just one device connected) after starting up the Mac. If you did not, and the problem all along was the USB port not able to connect to anything that is a storage device, your original extermal hard drive may have been OK.

In any case, if your Mac's USB port is not working properly now, try doing an these two trouble shooting steps for resetting SMC and PRAM.

http://support.apple.com/kb/ht3964

http://support.apple.com/kb/ht1379

If you can get your USB port to connect properly to your other external drive, iPod, and iPad, then go back and try the hard drive in its original case, to confirm there is still a problem. If there is, try the hard drive in the new case, to rule out the orignal case as the problem. And if it does not work either, you have ruled out the USB port, USB cable, and case as causes, so it is then likely that the cause is hard drive itself.

Hi

I seem to be having similar issues to those that have been mentioned above.

My Seagate 1TB external HD connects fine to my Macbook but will not connect to my newer and more powerful iMac. I have done everything mentioned above in regards to proving the the USB port is not at fault or the hard drive itself and it all checks out. When I do plug it in the the iMac i can hear the hard drive power up and the lights come on but no icon appears on any side bar not even in disk utility. The hard drive is formatted so the Mac's can read & write. Like I say, it is working fine on the MacBook.

Any ideas of why the iMac is not seeing it?

If you have ruled out a problem with the USB port and the USB cable, the cause is likely to be the hard drive itself. However, in your case, the hard drive works properly when connected to the MabBook. This is a USB 2.0 external drive?

Does the iMac have USB 3.0 ports? Maybe the external hard drive case (assuming it's USB 2.0) is somehow not compatible with USB 3.0. If you happen to have an older USB 2.0 hub that has its own power supply, as a test, try connecting the hub to the iMac and connecting the external drive to the hub. Does that make any difference?

The external HD is a USB 3.0 as are the USB ports on the iMac. The HD has it's own power supply which is always on for it to work. I actually had it connect for a brief period in which I was able to get some files off the HD and onto the iMac but after about 15 minutes the icon disappeared from the desktop and files were no longer visable.

Any other ideas?

Since it has its own power supply (it's not powered by the iMac's USB port), this must be a larger "deskop" external drive that has a 3.5-inch hard drive inside, is that correct? Does it just have the one data connection point on the back, for the newer USB 3.0 connector (which is different from the old USB 2.0 connector)?

If it has other data connection points on the back, what does it have? If you can find this product on Seagate's web site, can you include a link to its description page?

Yes. It is a 2 TB HD with just the USB 3.0 data connection point on it.

Here is a link the the HD:

http://www.seagate.com/au/en/external-hard-drives/desktop-hard-drives/goflex-des k/

Well, that should certainly work... Some things I can think of to try.

• You may not have another USB 3.0 storage device, but do you have an older 2.0 storage device that you can connect to the iMac's USB port? It could even be a USB flash drive, or an iPod. Just want to confirm the USB port DOES allow the system to mount some other storage device.

• If you happen to have another USB 3.0 cable, try it to rule out a faulty cable. It may work when connecting to a slower USB 2.0 port on the MacBook, but it may not be reliable at USB 3.0 speed.

• In case there is something "off" with the iMac's hardware, you can try the procedure to Reset SMC.

http://support.apple.com/kb/ht3964

For an iMac, this is just shutting down and disconnecting the power cord for at least 15 seconds and then reconnecting it. You may also want to do a Reset PRAM (although it should not matter for this type of problem)

http://support.apple.com/kb/ht1379

• Since this product is targeted at both Mac and PC users, it may be formatted using "FAT" (a disk format that is usable by both Mac and WIndows PC). You can try reformatting it (to the native Mac OS disk format) using Disk Utility. Since it does not work reliably with the iMac, you can do this using the MacBook. In Disk Utility, select the hard drive (the device) in the sidebar, not the volume indented below the hard drive. Go to the Partition tab. Under Partition Layout, select 1 Partition. Click the Options button. Make sure GUID Partition Table is selected. Name the volume (the one partition) as desired, and set the Format to Mac OS Extended (Journaled). Click Apply.

After the drive is repartitioned and reformatted, try connecting it to the iMac again to see if there is any difference.

dead SATA card, very common error, read all about it here:

Your dead external hard drive is likely fine! Great hope for your 'faulty' external HD

Kenichi

i have a big problem. I connected my hard drive to my MBA and it was showing up on disk utility and finder. But no data was being shown in the finder. I went to disk utility and repaired the hard drive. Since then the hard drive does not show up in finder and there are no options to repair it in disk utility as the option is greyed out.The hard drive was NTFS formatted and i was using it with Paragon for mac. This is the first time i attached it to my mac after the mavericks update. What should i do next?

Since you are using a third-party product to read/write data to NTFS (which to me is "scary"), you should check with the vendor to ensure it is compatible with the latest Mavericks update, and you have that version installed.

Also, this sounds like an exteral drive, so be sure to try the other things mentioned in this topic to rule out problems with the external drive enclosure or the cable that you are currently using. Also, try connecting something else (preferably something that is a storage device) to the same USB port to confirm it is working properly. If you are using a hub, try a direct connection to the USB port on the Mac with other USB devices disconnected.

hi, i bought a new macbook pro, trying to trasfer my data from vaio, through seagate 1.5TB external hard drive, formatted NTFS, was able to copy from vaio to HD, but now mac wont recognise the drive, cant see on disk utility, tried by restarting the mac, no other external devices attached..