MacOS – Bootable SSD and converting to APFS

apfsmacos

I boot my iMac from an external SSD, which is a clone of my main HDD, running Mojave. I had no issues before, recently with the Catalina being released I downloaded the update and when I choose my SSD drive I get: "this volume is not formatted as APFS".

What should I do now? I tried from recovery to convert it, but the option is disabled.

Is the only way to format it? or is there another way I am not aware of?

Best Answer

It turns out there was no way to change my SSD to APFS without formating. I ended up using "carbon copy cloner" cloned my SSD to internal hard drive, then formatted my SSD to APFS, and cloned everything back to SSD. All good now and I was able to upgrade without trouble.

Related Solutions

I can’t convert from HFS+ to APFS an external SSD volume I created for testing

According to this and this article the post-install conversion to APFS should work in Recovery Mode:

Boot the Mac into Recovery Mode by holding down the Command and R keys until you see the macOS Utilities screen.

Open Disk utility.

Choose your boot volume [the external boot drive].¹

Click on the Edit menu

Click on Convert to APFS

When prompted with “Would you like to convert to APFS?”

click on the Convert button. When the process is finished, click on the Done button.

¹: According to Redarm's comment you have to unmount the volume additionally!

I can't test this myself - your mileage may vary.

Using Carbon Copy Cloner 4 to create encrypted bootable HFS+ clones from APFS source

Here's what worked

Download the High Sierra installer from the App Store.
Run the installer, choosing the external clone disk as the target. This will automatically create a new Recovery HD partition associated with the target disk.
Reboot from the external disk. Hold down option key during startup to select the boot disk.
Enable FileVault encryption as usual from the Security & Privacy panel in System Preferences.

Additional Notes

You can reboot from your internal drive for better performance, after enabling FileVault on the external. The encryption task will continue as long as you're plugged into power and the external disk is connected.
It may take several hours, or even days, before encryption is done, depending on the volume of data to be encrypted.
You can view encryption task progress using the Terminal command diskutil cs list

What didn't work

There are some articles posted about how to clone the internal disk Recovery HD volume to any other drive, but I didn't have success with them:

$ diskutil list
/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *500.3 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                 Apple_APFS Container disk1         499.4 GB   disk0s2

/dev/disk1 (synthesized):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      APFS Container Scheme -                      +499.4 GB   disk1
                                 Physical Store disk0s2
   1:                APFS Volume Mac-HD                  431.9 GB   disk1s1
   2:                APFS Volume Preboot                 22.9 MB    disk1s2
   3:                APFS Volume Recovery                518.8 MB   disk1s3
   4:                APFS Volume VM                      2.1 GB     disk1s4

$ sudo hdiutil create ~/Desktop/Recovery_HD.dmg -srcdevice /dev/disk1s3
hdiutil: create failed - No such file or directory

I didn't find any articles that specifically addressed the case where the source disk is APFS format.

Best Answer

Related Solutions

I can’t convert from HFS+ to APFS an external SSD volume I created for testing

Using Carbon Copy Cloner 4 to create encrypted bootable HFS+ clones from APFS source

Related Question