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Suppose that we connect our flash USB drive to a MacBook, then eject this storage from Finder sidebar. Now I want to remount this storage without unplugging and replugging it into the computer, but the disk is no longer listed with diskutil list command.

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migrated from stackoverflow.com Feb 12 '12 at 15:00

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marked as duplicate by patrix Dec 2 '14 at 10:30

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3 Answers 3

You mount devices using:

diskutil mountDisk device

where device can be a

  • device node: /dev/disk2
  • disk identifier: disk1s7
  • volume mount point: /Volumes/Macintosh HD

For those that like the graphical Disk Utility.app, it also shows a connected drive that happens to not be mounted and you are able to mount ejected disks again from there as well.

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It looks like USB flash drives are a special case, which I hadn't noticed before. After ejecting the last volume the disk is removed from the device list, unlike most hard drives. However, using diskutil unmount or diskutil unmountDisk instead will unmount the volume(s) but leave the device connected for remounting. –  joelseph Feb 12 '12 at 15:49

The problem you describe was initially the intention for me to write an app that allows you to manage your drives from the menu bar. It is called Mountain and you can get it here.

Hope you enjoy it!!

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Can your app re-mount ejected drive? –  revolver Jun 13 '12 at 9:17
Mountain can re-mount unmounted drives. It is in general not possible to re-mounted ejected drives. That is why Mountain only unmounts drives and does not eject them. Unmounted drives can be either unplugged or re-mounted. –  Jannis Linxweiler Jun 13 '12 at 10:20
The only way to re-mount ejected external USB flash drives is to unload and load the USB mass storage kernel extension: kextunload /System/Library/Extensions/IOUSBMassStorageClass.kext; kextload /System/Library/Extensions/IOUSBMassStorageClass.kext Be aware that this will re-mount ALL external USB drives... –  Jannis Linxweiler Jun 13 '12 at 10:46

Disk Utility

No need for the commandline here. Open Disk Utility (/Applications/Utilities/Disk Utility), select your drive and click Mount.

Disk Utility

image comes from wikipedia

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The question is about ejected NOT unmounted or dismounted drives... –  PatrickT Oct 11 '14 at 7:15
@PatrickT, you CAN mount ejected drives within Disk Utility. –  CousinCocaine Oct 11 '14 at 8:33
After the SD/USB is ejected, it doesn't show in the Disk Utility: I tested it before commenting. Unless there's an extra step not detailed here, your suggestion did not work for me. Thanks though ;-) –  PatrickT Oct 11 '14 at 8:36
Here I have detailed an Automator solution based on other users' comments: apple.stackexchange.com/questions/62478/… –  PatrickT Oct 11 '14 at 8:38
@PatrickT, blame on me. you are right. It does work with USB hard-drives (which I tested) but does not work with USB-thumb drives. Sorry for my ignorance. –  CousinCocaine Oct 11 '14 at 14:36

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