If the internal hard drive disappeared from your iMac or Mac mini, you can check the internal hard drive in Terminal, especially for a internal Fusion drive. The reason is that when an internal Fusion drive is split, you can't see it showing up on Mac normally. I have connected my external hard drive to my new iPad pro. All the files show up ok on the iPad but all photos are faded and difficult to see. There are no messages coming up about a lack of power or anything else. The hard drive is a Toshiba 500gig. Document files and letters etc show up ok but photos are faded and unresponsive. As you said 'There are several reasons why Mac won't recognize a drive. If disk already mounted and system goes to sleep, it also powers down ports, including USB ports. When you wake your Mac up, for whatever reason, your external drive does not wake up'. It is right because generally sometimes an external hard drive doesn't show up on.
Why Won't My Seagate Hard Drive Show Up Mac
Why Won't My Hard Drive Show On Mac
- Make sure that you're using a backup disk supported by Time Machine.
- Unless you're using a network backup disk, make sure that your backup disk is connected directly to your Mac, not through a USB hub or other device.
- If your backup disk is connected directly to your Mac, use Disk Utility to repair the disk.
- If you're using a network backup disk, make sure that the network connection is good and your Mac is connected to the same network as the backup disk. If you completed a previous backup successfully, verify that backup: Press and hold the Option key while choosing Verify Backups from the Time Machine menu in the menu bar.
- Make sure that the firmware of your backup disk is up to date. Check with the manufacturer of the backup disk for details.
- If no other solutions work, start over: Erase your backup disk, then use Time Machine to select it as your backup disk again.
