Converting external SSD to APFS

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Level 6

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Converting external SSD to APFS

I have an external SSD with High Sierra formatted to HFS-journaled made by cloning (using CCC) my internal SSD with High Sierra and APFS. I was told that if I booted up from the external SSD in recovery mode I could use Disk Utilities to convert to APFS. However that option is greyed out. I also booted up in recovery from my internal SSD and the external SSD choice to convert to APFS is also greyed out. Why is that? (I have no reason the convert my external SSD to APFS just investigating the process.)

Posted on Dec 15, 2017 4:58 PM

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Answer 1

Barney-15E

Level 10

112,518 points

Dec 17, 2017 5:11 AM in response to tbirdvet

There is another thread of someone trying to do similar, although the drive has Sierra on it. I thought maybe that was the issue, but if you can't convert yours with High Sierra, I'm not sure.

Are you selecting the "Macintosh HD" to convert? In my searching I ran across an article that indicated you must select the Volume, not the drive.

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Answer 2

tbirdvet Author

Level 6

13,629 points

Dec 17, 2017 7:40 AM in response to tbirdvet

Did some digging on line and it appears that if the external drive is a clone (bootable) then you cannot use the convert to APFS in Disk Utilities. on this drive. So one must format to APFS before cloning to get this change.

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