External Hard Drive Not Mounting on Mac

Personal Computing

Your external hard disk refusing to appear (mount) on finder after being plugged in?

Reason

This generally happens if the hard disk was unplugged from the mac without ejecting it properly. When such a device is plugged in, the file checker utility fsck starts running automatically, preventing the disk from being mounted.

Soultion

Since its fsck that is causing the problem you can wait for it to complete running or just kill the process from the Activity Monitor or from the terminal as follows:

# check if fsck is running
$ ps aux | grep fsck

# kill fsck
$ sudo pkill -f fsck

Once fsck is killed, mac will mac should mount the disk as read-only. You can now back up the contents of the disk and try to fix it by running first aid on the disk from the mac Disk Utility program.

If that doesn’t work you might have to reformat the disk. Yes you will lose data if you format the disk.

Incase fsck wasnt running or if the disk still did not mount after killing fsck or if it doesn’t show up even on Disk Utility, the problem might be with the cable or the drive itself.