The disk number appears in a couple of places in the utility’s output. Reconnect the drive and power it up if necessary. Power down the drive if it has a power switch. (replace diskX with the number of the disk, like disk3). You may see multiple entries that start the same (as in the figure), such as disk3, disk3s1, and so forth. In the resulting list, find the disk number associated with the unmounted volume.
Plug the drive in and power it up if necessary. (This problem may affect drives formatted for Windows and macOS mounting more than HFS+ or APFS formatted drives, but it’s unclear.)įirst, you need to find out what macOS’s internal representation of the disk is: In some cases, you may be unable to remount a drive ejected early due to a power outage, shutting a computer down abruptly, or pulling a plug before macOS was ready.Ī few Terminal commands can help in at some cases, including solving a problem for one Macworld reader who had amassed three drives that could be mounted under Windows but macOS refused mount or allow Disk Utility to perform repairs on. MacOS alerts you when an externally connected drive was unmounted before the operating system had a chance to tidy up all the loose ends on it.
