After upgrading from OS X Sierra to OS X High Sierra on my MacBook Air, I can no longer mount and read my external hard drive. During the upgrade, I converted my MacBook hard drive to APFS. My external drive is formatted as Mac OS Extended.
Is the data on my external drive inaccessible now that I have APFS on my computer? Or is there a way to access it?
MacBook Air (13-inch Mid 2013), macOS High Sierra (10.13)
After hours and hours of research and testing I solved this for me.
When I plugged in my external hard drive it showed up in my drive in Disk Utility but it was grayed out.
I could not mount my hard drives and it would not let me repair, erase, nor partition them, an old and a new one.
I decided to click on the view button at the top right corner of my disk utility app and I had "Show Only Volumes" selected. So I clicked on "Show All Devices" and this showed me each device the volumes were on. I could now select my external hard drive and I was able to easily repair, erase, and partition my hard drives when I clicked on the device instead of just the volume.
I hope this helps anyone.
YES, this is the fix. You need to go to the Disk Utility, click on the little View button above the drive window on the left (for some mysterious reason unknown to mankind). Then, under the external drives you'll see your peripheral, not grayed out. You can then erase or mount the peripheral. Additionally, I contacted Seagate and they have a new driver for mine available -- I also downloaded and installed that. However, it made no difference until I used the magic view button on the native Mac Disc Utility. (Two days, phone calls, emails, restarts ...)
For the past few weeks, no matter which external drive I plug in and no matter which USD port, it wont' mount. Like other people here it shows up in Disk Utility as a virtual cd rom drive.
The only thing that works is restarting my iMac with the drive already plugged in.
But if I start up without an ext drive plugged in, I have to plug in and restart every time... not the greatest.
My WD harddisk appeared in the disk utility but not elsewhere.
I did command up in finder, 2 levels up from Users, or 3 levels up from current user to get to the volumes folder and pulled them out to the sidebar on the left. Hope it helps!
Still no solution for me. Toshiba 1TB pocket drive connected, nothing showing in disk utility and I have show all devices selected. Shut down iMac, drive seems to keep power (I left it a couple of minutes before unplugging). Plugged it back in and started computer. iMac takes ages to start but still does not recognise the device at all. My Samsung pocket drive is working perfectly. The Toshiba one is std OS journaled and holds all my content from my MacBook which is still running lion.
Yes. The drive shows up in Disk Utility, but will not mount.
You can't run First Aid on a disk that doesn't mount.
It doesn't show my Hard Drive on Disk Utility. It is connected to the laptop but it doesnt recognizes it. I dont know what to do anymore. There is not a single solution online.
Did you try mounting the disk in Disk Utility?
Restart seems to have solved my problem. 😕
Yeah, this is a bit ridiculous to leave unpatched.
btw, your nickname comes up as SteveS70 🙂
Go to utility disk. Tap with to fingers the name of your external drive then click Run First Aid... then you’re good to use it.
Mine is also doing this! MBP late 2011 and WD My Passport Ultra 2tb not working as well as WD My Book 4tb not working or mixing up the names and then saying the drives are damaged.
Yep, a simple restart solved my problems too.
Found a new driver on Seagate website (https://www.seagate.com/fr/fr/support/downloads/item/ntfs-driver-for-mac-os-mast er-dl/) that solves the write problem. Now my driver works well.
External hard drive not mounting Mac
