External hard drive won't mount in high sierra

My Toshiba Canvio is connected in System Information but doesn't mount. All of my research so far seems to agree it is due to the files system change. I always wonder what will stop when I accept these updates. Hope a fix emerges soon.

HS has about turned a 10 + year Mac user against them. I have lost so much time and money it's pitiful. If they don't get their junk together I will be selling a Macbook Pro, 27" iMac, iPad Pro and 2 new iPhone 8s and going to PC and android. Ever since Steve Jobs passed the company is going to the dogs. Get your act together Apple!

I guess waiting for an update makes the most sense?? I have a WD My Passport Ultra that is not recognized. I can see it in Disc Utility but it will not "mount". I noticed that the last High Sierra update was in mid December, which was when this hard drive (which I use for Time Machine), stopped working. Haven't had a backup since then. Ugghh.

Thank you for your insightful post. This is frustrating. I hope that Apple puts a fix in the next update because it seems that this issue is prevalent.

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.

THANK YOU!! I did this and checked the box that said "Show ALL Devices". Sure enough, I was able to reformat my brand new WD External Hard Drive and now I can read and write to it. Thought I was screwed by High Sierra. No more OS updates for me. Maybe.

vilko wrote:

Me. You create update that makes previous external disks unusable, and when people complain you poke fun at them? There should be a RED big warning that you are changing underlining filing system that will not be compatible with previous hardware.

External disks are not made unusable. You have a configuration or procedural problem. If you want assistance please start your own thread providing your system details and the details of your issue.

I am having the same issues with all my external drives. Either on MacBook Air or MacBook Pro. It's such a **** joke. But, hey, Apple: we have things like touchbars with smileys now. Who needs a machine that actually works?

Just a brief update. Once my Drobo had finished its own personal meltdown after the Time Machine folder debacle, I was able to reset it to the factory default and reformat it using Drobo Dashboard (losing all of my stored data in the process of course). Other than a single incidence of strange behaviour where it lost, re-found and then rebuilt a drive, it now seems to be behaving normally.

A new (late 2017) WD My Passport Wireless Pro also works fine, but all legacy drives (those a couple of years older or more) continue to present problems and will need to be cleaned and disposed of.

This is exactly the problem I'm seeing as well with my Seagate external drive.

Am waiting to hear back from 3rd-tier Apple Support. Spent 3 hours on Friday with them documenting the issue, but nothing worked.

Hi Tim

I've got the exact same issue.I can see the hard drive in DU and run a check/repair but it doesn't show in finder and I can't access any files. have you found a fix .

I also try unticking everything in spotlight it didn't help at all

same as you it worked fine before I installed High Sierra, it's really terrible that mac can be so difficult to connect with other systems sometimes, such a waste of time for something that should take 5 mins...

Thanks!

Cyndie

I have the same problem. External 4T Seagate disk drive. Running High Sierra on a 2015 MacBook Pro. Disk Utility can't mount it or repair it. TechTool Pro 9 can't repair it. My computer keeps warning me that it has been removed without ejecting it when it's still plugged in! Now it won't come up on the desktop at all. This is my Time Machine backup external disk and I need everything that it holds in addition to the backups. Please, Apple, help us with this!!!

Strange, usually the other way around.

ssspol wrote:

High Sierra is deemed one of the worst OSX updates in Apple's history

Other than you who is it that deems HS as the worst update in Apples History?

Mine appears to power up but LED is a different colour to normal. Disc is spinning but no access at all. Disc utility can't see the drive at all