Encrypt external ssd on mac sonoma?

[Joeronzk]

I back up my data on Mac to external ssd manually once two weeks and for security reason, my goal is to encrypt the external ssd with a password, similar to BitLocker on Windows. When I access the content, the password is required.

P.S. I don't like the Time Machine backup option.

Thanks

 

[bob_zz123]

Easy to do - just follow instructions here: https://support.apple.com/en-gb/guide/disk-utility/dskutl35612/mac

WARNING: You will have to erase the drive so if there's anything stored on it that you need to keep, copy it somewhere else safe first.

 

[chabig]

The above works, but since you already have data on the drive it's a bit of work to make a backup, reformat the drive, and copy the data back. Far easier is to add encryption to the data in place:

Protect your Mac information with encryption

On your Mac, you can encrypt information on removable media such as CDs, DVDs, and memory cards and require a password to decode it.

support.apple.com

 

[Joeronzk]

Easy to do - just follow instructions here: https://support.apple.com/en-gb/guide/disk-utility/dskutl35612/mac

WARNING: You will have to erase the drive so if there's anything stored on it that you need to keep, copy it somewhere else safe first.

I am going to try on a new disk, so no need to worry about that. Thank you

 

[Joeronzk]

The above works, but since you already have data on the drive it's a bit of work to make a backup, reformat the drive, and copy the data back. Far easier is to add encryption to the data in place:

Protect your Mac information with encryption

On your Mac, you can encrypt information on removable media such as CDs, DVDs, and memory cards and require a password to decode it.

support.apple.com

Which format should be used, APFS or HFS? I need to access it on old Mac like MBP Late 2015.

 

[Mike Boreham]

The above works, but since you already have data on the drive it's a bit of work to make a backup, reformat the drive, and copy the data back. Far easier is to add encryption to the data in place:

Protect your Mac information with encryption

On your Mac, you can encrypt information on removable media such as CDs, DVDs, and memory cards and require a password to decode it.

support.apple.com

Just a caution about the Finder method @chabig mentions. It is certainly easier but it takes a long time. There is no easy way to monitor progress but you can use it normally while it is going on. The reformat and copy back is quicker.

John Daniels of Etrecheck fame told me how to monitor progress on an APFS external: Typediskutil apfs list -plist into Terminal window and search for “CryptoMigrationProgressPercent”

 

[Mike Boreham]

Which format should be used, APFS or HFS? I need to access it on old Mac like MBP Late 2015.

It’s not the age of the mac that matters but the macOS version it is on. APFS came in with High Sierra so if it is on that or later you should be OK to use APFS.

Many would say that if the disk is a spinning HDD, you should still chose HFS+ as there are some penalties with APFS on spinning HFS+ but these are mostly related to speed when using APFS on a boot drive. For backup use APFS should be fine, and Apple forces APFS for Time Machine backup drives. But for a backup spinner there is maybe not a lot of advantage for APFS which was designed for SSD.