could not unmount disk external hard drive time machine

The method I’m showing here requires some familiarity with the Terminal application, which can be found in /Applications/Utilities. You can’t just use Disk Utility to reformat an APFS disk to HFS+ - once it has been converted to APFS, the only options that appear for erasing an APFS disk are to reformat in APFS. In this tech tip, I’ll show you how to revert back to HFS+. What if you accidentally format a drive in the APFS format and then realize you can’t use Time Machine or FileVault 2? I recently ran into this dilemma when I formatted an external drive in the APFS format and it was unusable by Time Machine. For example, APFS is incompatible with Apple’s Time Machine backup application and FileVault 2 (which is used to encrypt full drives), and cannot be used to format Fusion drives - those drives that use a combination of a solid-state drive and conventional hard disk drive. However, there are still some instances where HFS+ needs to be used. Check out this new article to see how to revert an APFS drive to HFS+ easily.Īpple’s new APFS (Apple File System) format is the default format for storage under macOS 10.14 Mojave, replacing the dependable and long-lived HFS+ format. Press Command+Space, type Disk Utility, and press Enter to open it.Changes to macOS and Disk Utility in macOS 10.15 Catalina now make this older method obsolete. You’ll need to use the Disk Utility built into your Mac to work with partitions. You can also make the files partition an ExFAT partition, which means you can use it with Windows PCs and practically any other device you can connect an external drive to. This will ensure your Time Machine backups don’t grow too large, so you’ll always have room for your personal files. Use one for Time Machine backups and another for your personal files. The ideal way to do this is to create separate partitions on the external drive. I could see it in Disk Utility (on both OS’s). It would say all good, but the drive would NOT mount.

RELATED: What's the Difference Between APFS, Mac OS Extended (HFS+), and ExFAT? Time machine external became unmountable in (running El Capitan) but I also tried it on a different mac running Leopard (yes,) still didn’t mount.

A Better Option: Create Separate Partitions for Backups and Files Time Machine will also work toward filling up the entire drive, not leaving extra room for your files. Bear in mind that Time Machine requires the drive be formatted with the Mac’s HFS+ file system, which means you won’t be able to easily access these files on Windows PCs or anything else that isn’t a Mac.

Could not unmount disk external hard drive time machine