Can't Access part of my 6 TB USB drive

[Aimireal]

My Mac stopped booting up. It was stuck on the Apple logo, so I installed an OS on the USB drive so I could fix the internal drive. That worked fine until I went to access the USB external drive (6TB) and found out I could not access any other files. Disk Utility shows the files are still on the drive but under the name “Drive Name - Data”.

How do I gain access to the other files?

Thanks in advance.

 

[gilby101]

My Mac

You will get more focused replies if you say what model of Mac and what version of macOS. To clarify your disk configuration it will be useful if you add the output from the Terminal command diskutil list. Also what backups you have.

 

[Fishrrman]

The "USB drive" -- is it a platter-based hard drive?

More recent versions of the Mac OS don't do so well on platter-based drives -- not fast enough. Some won't work as a boot drive at all.

As gilby asks, what Mac do you have? What year was it made? What version of the OS was running?