Reader's question: Mac startup disk with APFS / upper and lower case causes problems

APFS is case sensitive

Today I received an email from "Mischu", a reader who had a little "mishap" while installing his Mac. I have summarized the content here:

Today I completely reinstalled my Mac, but I didn't select "APFS" during setup, but "APFS - upper/lower case". I noticed this because the installation of the Adobe CC installer did not work.

What disadvantages will I get with other apps? Can I change this later to “APFS”? Or should I create a backup, reinstall the computer with "APFS" and then restore from the backup?

Oh s *** t. I have the stupid feeling that at some point something will fly around my ears. Can someone help or enlighten?

Not all apples are the same - what are the advantages of differentiating between large. and lower case in macOS?
Not all apples are the same - what are the advantages of differentiating between large. and lower case in macOS?

Not all apples are the same ...

I still know the problem with the distinction between upper and lower case from hostings that ran either under Linux or under Windows. While Linux servers are careful with upper and lower case and report a file as "not available" if you linked "apfel.jpg" instead of "apple.jpg", a Windows computer usually doesn't care .

Since I've known the Mac, it's not case-sensitive, and the startup disk of new Macs is always formatted WITHOUT this option. Developers who write software for the macOS platform (such as Adobe) are accordingly prepared for the fact that the Mac is more “accommodating” with file names. Actually, Linux is more precise here, because a "mal" is something different than a "mal", but we are here with macOS and there one is more tolerant with the file names.

In a Forum I found the following explanation:

[…] The upper / lower case variant actually only has disadvantages for desktop systems / notebooks. For example, many Adobe products cannot be installed with it (e.g. the current Photoshop Elements). And then that with FileVault. And so on.

Extended upper / lower case can do just that: In a folder e.g. B. Save "amarok" and "Amarok" and "aMarok" as three files. But if a program assumes that it is not case-sensitive, there are problems.

So format to Extended WITHOUT upper / lower case letters, then everything should do. That may change in the next few years, but right now? So you just have less stress.

So: The recommendation is: Always format the hard disk WITHOUT this distinction between upper and lower case. Personally, I am also not aware of any advantage of this option.

With which file system does Apple deliver the Macs?

I've often wondered what the "upper and lower case" option is for, but so far for "security reasons" I've only ever used the normal HFS+ and APFS variants when formatting the hard drives, since Apple itself uses them by default used by the Macs they ship. Now how do you get the boot volume on APFS without the case sensitive option without doing a complete rebuild?

Conversion to APFS with backup software

The solution is: an external hard drive and a Backup program like SuperDuper or Carbon Copy Cloner to use. The external hard drive comes with the Disk Utility first formatted to the “APFS” format (no upper and lower case!), because the disks are usually delivered by the manufacturer in ExFAT format. If that doesn't work right away, there is here are instructions.

Then the software copies a bootable backup from the system hard drive to the external hard drive.

In the next step, we boot the Mac from the external hard drive (press and hold the "ALT" key during system startup until a selection appears) and see if all the important data is still there. This should usually be the case, since the backup programs check the data after the backup has been created.

If everything worked, we go back to Disk Utility and reformat the internal hard drive to “APFS” (case-insensitive!). Then we copy all the data from the external hard drive back to the internal hard drive using the backup program of our choice.

Now we put under “System Preferences > Startup Disk” set the internal hard drive as the startup disk again (if that should have changed) and reboot the Mac. It's best to unplug the external hard drive so that we can be sure that the Mac is using the internal hard drive.

If it boots up cleanly, the installation with the Adobe CC Installer should go through cleanly and you have a "risk-free file system" to start with.

My tips & tricks about technology & Apple

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2 Responses to “Reader Question: Mac Startup Disk with APFS/Case Sensitive Causes Problems”

  1. Oliver Kapffer

    It does not work that way. The existing partition on the target is deleted (at least by SuperDuper!) And a new partition is created with the same properties as the one to be copied.

    1. Hello Oliver! I didn't buy the full version of Super Duper as I already paid for Carbon Copy Cloner, but I imagine you can turn off target drive reformatting in the options somewhere. In any case, nothing is formatted with Carbon Copy Cloner.

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