External hard drive not accessible after plugging in.

[Haroun]

I have just bought 2 Toshiba Canvio Flex 4TB Portable External Hard Drives & when plugged in I get a can't be read message & the choices to Initialize, ignore, or Eject. They show in Disk Utility as not mounted. Any idea what I can do to get them to work? I've restarted a number of times & they still don't work.
I have a Imac 27" late 2013, 3.4 Quad i5.
Thanks

 

[Slydude]

Typically that message occurs when an external drive is formatted so that the Mac cannot read without third-party software. Since these are new drives and don't have anything on them that you need to, When Disk utility launches, you can format the drive to something your Mac can use. Choose Initialize.

Erase and reformat a storage device in Disk Utility on Mac

In Disk Utility on your Mac, erase and reformat a storage device to use with a Mac.

support.apple.com

 

[chscag]

Point of information: All Toshiba drives come pre-formatted to NTFS which is a Windows file system. As our Moderator Slydude states, you will need to reformat them to a Mac file system.

 

[Slydude]

Good point, Charlie. It has been a while since I bought a Toshiba drive, so I didn't realize they were doing that with all their drives.

 

[Haroun]

They won't mount to be reformatted. How do I reformat if they won't mount?

 

[MacInWin]

In Disk Utility, click on "View" and then "Show All Devices." The drives should show in the left column with their hardware names, probably with Toshiba in the name. Select that hardware level, then "Partition" on the top menu, give a name, use APFS format and GUID partition scheme. Let it format. At the end you will have a drive formatted APFS that will mount as whatever name you gave it.

 

[IWT]

when plugged in I get a can't be read message & the choices to Initialize, ignore, or Eject.

Choose "Initialise", then follow the directions given. The Drive should then mount and you can follow the wise advice given above.

If that doesn't work, there may be a fault with the Drive. It can happen straight "out of the box".

Ian

 

[Haroun]

Thanks for all your help, I've got them to mount & get reformatted, now they sometimes show, sometimes don't show in finder & disk utility. That may be the usb hub, or the computer itself given the age. Oh well. I'll do a restart & see what that does.

 

[MacInWin]

That may be the usb hub,

Most likely. Is the hub powered? It should have it's own power supply if you are going to attach drives through it. Otherwise you can overload the power demand on the USB port on the Mac.