Why does my Macbook Pro abruptly not recognize the formatting of my LaCie external hard drive?

christiane212 wrote:

I have a late 2013 Macbook Pro running Catalina. Last year, my old external hard drive stopped working so I acquired a new 2TB LaCie one. It's plugged in almost all the time because I am paranoid about backing up. Anyway, two weeks ago, a new and unusual problem showed up -- the computer, though it recognized the LaCie, claims that the hard drive was not in Mac OS Extended (Journaled) format and refused to back up to it. I went into Disk Utility, re-partitioned the LaCie to Extended (Journaled) Encrypted. That worked for awhile, then the same problem happened. Repartitioned the hard drive and set it back to Extended (Journaled). Worked fine, until it abruptly didn't today.

Is it the computer or the hard drive? I hear that LaCies can be buggy. So before I go splurging on a new external hard drive, I'd like to get some answers. Thanks!

Sounds like the external drive is operating in a state of failure. Replace it.

All new drives should be erased and formatted before you use them out of the box.

Erase and reformat a storage device in Disk Utility on Mac

https://support.apple.com/guide/disk-utility/erase-and-reformat-a-storage-device-dskutl14079/19.0/mac/10.15