2020 MacBook Pro won't mount WD external hard drive It's formatted HPS+. Mounted fine yesterday (and for a long time before that). Now, the light on the drive blinks on-and-off and it sometimes briefly shows up in the output to diskutil list as /dev/disk3. I've tried diskutil eject disk3 and similar variants.
The drive automatically mounts on linux without issue.
I do not see fsck running (I checked with ps auxw and top from a terminal). I did not find any interesting log messages via the Console program.
We had trouble about a year ago. Apple support recommended upgrading the OS and I think that worked. We also bought a second cable for the external drive, but ended up not needing it. I just tried the second cable and it didn't make a difference. There was an upgrade OS available and we tried that after talking to Apple support this time, but it didn't make a difference. The drive mounts fine on a ~2016 Mac Air.
A few days after posting this, we got a usb-c cable for the drive and had no trouble using the drive with a direct connection. A few days later, the hub that we were using to connect the drive completely died. So, the hub was clearly the problem.