Not recognizing external hard drive

Had the same symtoms. After re-connecting the drive it wasn't recognized. Did this several times, but:

I gave it a last try, had to leave the system for 1/2 an hour alone. When I came back, the drive was mounted.

My thought: During mount OSX checks/repairs the disc, which needs time.

Same happens with a second drive which wasn't recognized any more, as I thought.

I know this post is a couple years old but it did help me.

Thank you.

I'm having the same issue:

- Apple Logo > About this Mac > System Report > USB shows "BUP Slim Mac SL", with Manufacturer Seagate.

So the USB is recognizing my external HD. But the Mac Operating System isn't able to recognize the device as a hard drive. Going to try downloading the driver.

It's not even mounted for some people..

Actually, it didn't solve the problem for long. Found this CNet article that may help some people.

https://www.cnet.com/news/troubleshooting-external-hard-drives-that-will-not-mou nt/

1) Connect HDD

2) Go to Disk Utilities

3) Selected HDD

4) and then clicked on First Aid. It starts the recovery.

5) Unmount the HDD & then again after mounting the HD, the HDD was visible

mine is doing the exact same thing. Need Help