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Andre John Mas Author

Level 4

1,083 points

External hard drive won't mount in high sierra

Is something broken in High Sierra when it comes to external USB HDs? Did something break in the USB stack?

Up until installing High Sierra I have been able to mount my external USB hard-drive with my MacBook Air. I now try connecting it and it will not longer mount. It isn't even listed in the USB devices section, when I check "System Information".

Originally I thought the drive was broken, but I did some digging and none of my Seagate drives will mount. Same issue with all of them (I have three Seagate drives: 2 FreeAgent GoFlex and 1 Backup Plus Portable Drive). They don't appear in the list of USB devices and no LED activity of the drives. They are all USB 3.0 based drives.

They all work on my old Mac Mini, which is running macOS 10.11.6. Two of the drives are HFS+ and the other is NTFS.

An older USB 2.0 based drive mount fine.

I am using macOS 10.13.1 on the MacBook Air.

MacBook Air, macOS High Sierra (10.13.1), null

Posted on Nov 12, 2017 8:07 AM

Top-ranking reply

ssspol

Level 1

9 points

Posted on Dec 18, 2017 7:01 PM

I don't believe it has anything to do with USB. It doesn't work for me when using both USB and Thunderbolt. After some digging, I think it all has to do with High Sierra and APFS. High Sierra is deemed one of the worst OSX updates in Apple's history and it could be simply just a lack of support for spinning HDD drives and that's why nothing will mount. Unfortunately, that makes this a waiting game for an update to fix all of this due to Apple leaving HFS+ and going to APFS.

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59 replies

Jan 21, 2018 5:13 AM in response to mrmcsmitty

Doesn't reformatting mean you lose all your files???

Csound1

Level 9

60,033 points

Jan 21, 2018 5:41 AM in response to SpiralDreamer

SpiralDreamer wrote:

Doesn't reformatting mean you lose all your files???

Yes it does, unless you have a backup

Jan 25, 2018 9:46 AM in response to tbirdvet

Thank you so much!! I had spent hours troubleshooting a brand new Western Digital Elements hard drive. As soon as I did this, the OS had no problem formatting to Mac OS Extended. You rock!

ioscev

Level 1

8 points

Mar 3, 2018 2:54 PM in response to Al_J_H

Same problem here.

NYCMoi

Level 1

8 points

Mar 6, 2018 3:29 PM in response to MasterNater

Which thing did you do that actually worked, please? Getting desperate over here!

NYCMoi

Level 1

8 points

Mar 6, 2018 3:44 PM in response to BRN2SHN

Could you explain what you did in more detail, please? What did you search for in Spotlight that you then turned off? Did you reboot before you connected your external HD?