It's a Seagate 2TB Expansion hard drive. Seagate says it's an Apple Time Machine permissions problem.
the other issue that comes up is if that is a NEW drive, that shipped from the factory as a non-Mac format.
Drives like the MyBook come with software, and the manufacturer suggested you install that software.
What that software does is to "spare you the annoyance of having to re-initialize the drive" from its factory set Windows New Technology File System (NTFS, the W is silent because there ARE no other Operating Systems) or similar unusual (on a Mac) format. Instead, the software they provided would simulate a MacOS drive inside an NTFS file for your Mac. in some cases, that may not be good enough for Time Machine.
The downside of using the manufacturer's software is that if the manufacturer's software is not loaded, the Macintosh Volume may not readable, or may not be writable. This means that in startup manager, Installer, and in Recovery such as after a data loss, the Macintosh Volume may not be visible.
The standard advice given here to all users, including novice users, is to discard the manufacturers software and NEVER use it. "Best Practice" is to erase the physical device when new, using only MacOS Disk Utility, and create the fundamental data structures needed for consistent, reliable use by MacOS.
Be sure to "show all devices" which will allow you to ERASE the entire Physical Device by its immutable manufacturer-given device-name, not just user created Volume-name such as ‘Macintosh HD’.
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When you try to completely erase a device with a "foreign" format like NTFS, MacOS usually refuses.
But you can ask it again, immediately, and it will often proceed. It's as if they left out a MSDOS-like dialog, "Are you sure?"
Erase and reformat a storage device in Disk Utility on Mac - Apple Support
the other issue that comes up is if that is a NEW drive, that shipped from the factory as a non-Mac format.
Drives like the MyBook come with software, and the manufacturer suggested you install that software.
What that software does is to "spare you the annoyance of having to re-initialize the drive" from its factory set Windows New Technology File System (NTFS, the W is silent because there ARE no other Operating Systems) or similar unusual (on a Mac) format. Instead, the software they provided would simulate a MacOS drive inside an NTFS file for your Mac. in some cases, that may not be good enough for Time Machine.
The downside of using the manufacturer's software is that if the manufacturer's software is not loaded, the Macintosh Volume may not readable, or may not be writable. This means that in startup manager, Installer, and in Recovery such as after a data loss, the Macintosh Volume may not be visible.
The standard advice given here to all users, including novice users, is to discard the manufacturers software and NEVER use it. "Best Practice" is to erase the physical device when new, using only MacOS Disk Utility, and create the fundamental data structures needed for consistent, reliable use by MacOS.
Be sure to "show all devices" which will allow you to ERASE the entire Physical Device by its immutable manufacturer-given device-name, not just user created Volume-name such as ‘Macintosh HD’.
--------
When you try to completely erase a device with a "foreign" format like NTFS, MacOS usually refuses.
But you can ask it again, immediately, and it will often proceed. It's as if they left out a MSDOS-like dialog, "Are you sure?"
Erase and reformat a storage device in Disk Utility on Mac - Apple Support
Assuming you're an Admin user ... Open Finder.
Right click the drive in question and select "Get Info"
Once you allow access, Ventura has a little gold padlock to do that with, you can set permissions. You gave no detail on your OS versions so this is for illustration only unless you are running Ventura.
Once "unlocked" your can give your user permission.
Thanks for the reply! I really appreciate it. I'm still getting the error message about Time Machine permission. Can you tell me how to specifically allow Time Machine to use the Seagate hard drive? Also, I'm running on High Sierra 10.13.6.
I'm trying to use an external 2TB drive for back up but I get the message "There was an error preparing the Time Machine backup disk." I can't get around it.k
