External drive hardware errors like bad sectors.Virus infection that comes from recently downloaded files, applications, patch, etc.The outdated disk driver that appears if you haven’t updated your software and hardware for a long time.Power supply failure, especially when MacBook is in low power mode and external hard drives requires extra power resource.Faulty connections such as the wobbly USB port and broken USB cable.The hard drive is encrypted or password-protected, especially for Seagate Backup Plus Ultra Touch hard drive.A recent macOS update or software update, which could cause many types of incompatibility.The causes for Seagate Backup Plus drive not detected issue could be: And here are some possible causes for this problem. And sometimes the external hard drive even greyed out in Disk Utility. Why Seagate Backup Plus drive not showing up on Mac?Īctually, it's a common issue that the Seagate Backup Plus drive is not recognized or detected. In this case, you can't see files on the external hard drive or access them at all. So, it's important to know why and how to fix when Seagate Backup Plus drive is not showing up on Mac. I searched for all day but no Seagate firmware update available (attempt to update shows it to be current) and no other help available from Seagate 'support.' Can anybody help me cuz I'm really in need of the files on this drive？ I can see the light on HD so I am sure it is getting power. Since I upgrade to Yosemite (maybe coincidental?) the HD is no longer recognized by my MacBook Pro. I use a Seagate 2TB Backup Plus Portable HD as my Time Machine backups drive and it had been working fine.

Seagate hard drive not showing up