New External SSD won't format, stuck at this screen

I just bought a 4 TB SanDisk Extreme Portable SSD. I’ve tried to erase/format it with Disk Utility on two different computers: a new 14" MacBook Pro, and a 2017 iMac Pro. I clicked on the external volume, selected erase, then AFPS for file system, then clicked the “Erase” button. The drive disappears from the desktop, but Disk Utility seems to get stuck on the “Unmounting Disk” step. It says “Erasing ‘Extreme SSD’ (disk4s1) and creating ‘Photos’” and then under that it says “Unmounting Disk”, but after 10 minutes nothing has happened.

What’s going on?

1 Like

Hi @matt.sbc
Have you opened a Support Case? If not opened, for more information, please contact the SD Technical Support team for best assistance and troubleshooting: