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.
1. Restart Your Mac and Use First Aid Feature of Disk Utility : Begin by rebooting your MacBook Pro, then launch the Disk Utility application. Select the problematic drive and run the “First Aid” tool to check for & repair any disk errors.
2. Attempt to Erase the Volume: If the drive still isn’t functioning properly, try erasing the entire volume using Disk Utility. This will wipe all the data (ensure you have backups if needed). After erasing, you can reformat the drive for future use.
3. Force Unmount the Drive Using Terminal: In some cases, the drive might be stuck or unresponsive. Open the Terminal application and force unmount the drive using a specific command. This will help detach the drive safely if it’s being stubborn about ejecting.
4. Force Erase the Disk via Terminal: If the volume can’t be erased through Disk Utility, you can use Terminal to perform a forced disk erase. This can be useful when regular methods fail, but be careful as it will delete all data on the drive.
5. Reduce the Security Level: macOS has built-in security features that can prevent certain drives from being erased or modified. You can temporarily lower the security settings to allow the disk operations to proceed. Be sure to return security settings to their normal level once you’re done.
6. Delete Partitions: If the disk is partitioned and causing trouble, you may need to delete the existing partitions. This can be done in Disk Utility by selecting the drive and removing the partitions, allowing for a fresh start.
7. Format the Drive in Safe Mode: Boot your MacBook Pro into Safe Mode by holding down the Shift key during startup. In this mode, macOS disables unnecessary software and services, which can help you format the drive without interference from background processes.
