disk utility won't format USB stick to APFS

ReptileMoebus wrote:

did that just now. no resolution. still error message "erase process failed". interestingly, after I selected file type APFS and GUID partition map scheme, during the erase process, disk utility suddenly changes to formatting for "macOS journaled". disk utility has never done that before.

I have seen this happen for several years now and it appears to be normal, but I think it with recent versions of macOS I have seen it directly create an APFS volume instead of an HFS+ volume and converting it.

I have also seen Disk Utility fail to erase a drive even when the physical drive is selected. Most times if I immediately try erasing the physical drive again, the erase process will succeed. Disk Utility is not a great app and has a lot of odd behaviors.

I have also seen macOS have problems erasing drives which have been created using other operating systems or devices. Again, macOS isn't very smart when it encounters something unexpected. When this happens I will write zeroes to the beginning of the physical drive to destroy the partition table so that the drive appears "blank" and factory fresh with no partitions or file systems. Disk Utility will usually erase the drive successfully. To write zeroes to the beginning of the drive you need to get the drive identifier for the physical drive which can be retrieved from Disk Utility. The drive identifier will be in the form of "diskX" where "X" is a number, for example "disk3". In the following commands replace "diskX" with the correct drive identifier for your USB stick.

Unmount all volumes on USB stick "diskX":

diskutil  unmountDisk  diskX

Write zeroes to the beginning of USB stick "diskX":

sudo  dd  if=/dev/zero  of=/dev/diskX  bs=100m  count=10

This last command will prompt you for your admin password, but nothing will appear on the screen as you type the password. Press the "Return" key to submit the password.

If you use the wrong drive identifier, you may accidentally destroy important data, so be very careful to have the proper drive identifier for "diskX". It is recommended to disconnect all external devices to minimize confusion and to minimize the chance of destroying data on those devices. Plus make sure to have a good backup before using the command line since there is no safety net if a mistake is made.

Now use Disk Utility to erase the physical USB stick as GUID partition and APFS (top option).

Keep in mind the quality of most USB sticks is extremely poor, plus Macs tend to be a bit particular about the drives used. In addition, both macOS 12.x Monterey and M1 Macs both have some compatibility issues with external devices.

Perhaps this - instead id Erasing the drive - Repartition the drive as a single Partition and format as APFS / GUID Scheme.

Doing so will remove the existing Partition Map and lay down a new one.

Did you make sure the flash drive was partitioned as GUID? That's required for APFS. (I believe the default partition scheme on nearly all flash drives is Master Boot Record.)

I had a drive that would not unmount via the Erase process. I then tried unmounting it separately via Disk Utility and then erasing and it worked like a charm.

ReptileMoebus wrote:

interestingly, after I selected file type APFS and GUID partition map scheme, during the erase process, disk utility suddenly changes to formatting for "macOS journaled". disk utility has never done that before.

I noticed that as well, although it makes no difference as to the outcome. The drive is still formatted as APFS. I don't know if it ever did it before or not. Not something I paid attention to.

You're welcome.

It's the arrow to the right of the device name:

Good work: -)

Then for the benefit of Others looking in on this question - suggest Marking your post above as " Solved " green badge