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disk utility bug in Mac os 12?

I am using disk utility to format a USB Stick in ms-dos, fat but after I click ERASE the drive is formatted in ms-dos fat 32. That is a big problem for me because other devices won't recognize the stick anymore.


Why is that happening?


I wasn't having that problem with Mac OS Mojave.

Posted on May 28, 2022 12:52 PM

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Posted on Jun 3, 2022 5:12 PM

I was able to use disk utility to format in ms-dos fat (period, not 16, not 32/ exactly like you see in the upper photo ).

There is no such thing as FAT (period). File Allocation Table is the type and the -XX is the size of the table. There was likely a FAT-8, but the only reasonable size to date is FAT-16 or FAT-32. It doesn't matter what the label in Disk Utility says.


You may have somehow created a GUID Partition Table (GPT). Based on the list of formats available (encrypted), the drive has a GPT. Most automobile devices can't understand a GPT. They need Master Boot Record (MBR).

In Disk Utility, select Show All Devices from the View popup menu. Select the device from the list and Erase that. Set the partition map to MBR. Set the format to MS-DOS (FAT).

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Jun 3, 2022 5:12 PM in response to razvanpopa81

I was able to use disk utility to format in ms-dos fat (period, not 16, not 32/ exactly like you see in the upper photo ).

There is no such thing as FAT (period). File Allocation Table is the type and the -XX is the size of the table. There was likely a FAT-8, but the only reasonable size to date is FAT-16 or FAT-32. It doesn't matter what the label in Disk Utility says.


You may have somehow created a GUID Partition Table (GPT). Based on the list of formats available (encrypted), the drive has a GPT. Most automobile devices can't understand a GPT. They need Master Boot Record (MBR).

In Disk Utility, select Show All Devices from the View popup menu. Select the device from the list and Erase that. Set the partition map to MBR. Set the format to MS-DOS (FAT).

May 28, 2022 4:37 PM in response to razvanpopa81

In your screenshot only "FAT" and "exFAT" are shown. Typically "FAT" will be FAT32 on macOS. If the drive is too small for FAT32, then I believe macOS may format it as FAT16 (or at least it used to do so). exFAT is not FAT32.


You may be able to select FAT16 if you want to use the command line to format the drive. You will need to the drive identifier which you can get from Disk Utility (it is in the format of "diskX").


Once you have the drive ID, then you will need to unmount all volumes on the drive you want to erase. Make sure you have the correct drive ID or you will destroy all data on the wrong drive. Make sure to replace "diskX" in all of these commands with the correct drive ID for your drive (always verify the drive ID immediately before using the command because it may change each time you mount the drive).

diskutil  unmountDisk  diskX


Now there may be two ways to format the drive. I'm presenting both options here since I'm not sure if Monterey may have changed something. I've never personally used the first option, but only found it when searching just now. Make sure to replace "MYDRIVE" with the name you want for the drive (use all caps within the double-quotes, maximum eleven characters).

sudo  newfs_msdos  -F 16  -v "MYDRIVE"  /dev/diskX


This will prompt you for your admin password. As you type the password nothing will show on the screen so you will need to press the "Return" key to submit the password.


diskutil  eraseDisk  "MS-DOS FAT16"   "MYDRIVE"  diskX


I do not know what type of partition table these commands will make, but most likely it will be GUID. I also don't know which partition type you actually need for your device. Most likely you will need the MBR partition type. If the above commands don't give you the partition type you need, then you can use the following command which allows you to select the partition type (I'm going to show it with the MBR partition type, but it can easily be modified to GUID by replacing "MBR" with "GPT").

diskutil  partitionDisk  diskX  1  MBR  "MS-DOS FAT16"  "MYDRIVE"  R


Here is the post I found which provided this information (except for the last option):

https://apple.stackexchange.com/questions/226975/how-to-create-a-fat16-partition-on-an-sd-card-with-os-x-el-capitan


Always be careful when using the command line within the Terminal. It is extremely easy to make a catastrophic mistake since there are no safety nets like the macOS GUI provides. Use these commands at your own risk. I have not personally tested these commands to verify I have them 100% correct, but should work as written as long as you replace "diskX" with the correct drive ID.


May 30, 2022 12:58 PM in response to HWTech

I was able to format my USB stick (2GB) in FAT 16, but it still doesn't work with my car's device (error: no file).

Another stick (32GB) format FAT32, written by my MAC os 12 displays the same error in my car's device.

Another old stick (8 GB) written in a PC was ok. my car's device played all the media files from the stick.

When I used MAC os Mojave (2 weeks ago) I was able to use disk utility to format in ms-dos fat (period, not 16, not 32/ exactly like you see in the upper photo ).

I had no problem at all.

Now, like I was saying in the first post, the ms-dos fat option, although apparently available, leads to the same ms-dos fat 32 format.

I concluded that is a bug and that is nothing to do about it in this version of MAC os (12.3.1)

May 30, 2022 6:04 PM in response to razvanpopa81

razvanpopa81 wrote:

I was able to format my USB stick (2GB) in FAT 16, but it still doesn't work with my car's device (error: no file).
Another stick (32GB) format FAT32, written by my MAC os 12 displays the same error in my car's device.
Another old stick (8 GB) written in a PC was ok. my car's device played all the media files from the stick.
When I used MAC os Mojave (2 weeks ago) I was able to use disk utility to format in ms-dos fat (period, not 16, not 32/ exactly like you see in the upper photo ).
I had no problem at all.
Now, like I was saying in the first post, the ms-dos fat option, although apparently available, leads to the same ms-dos fat 32 format.
I concluded that is a bug and that is nothing to do about it in this version of MAC os (12.3.1)

You may want to see if you can tell what block sizes or file allocation sizes are being utilized. I believe the "newfs_msdos" command allows selecting more of the FAT options, but I have no clue what to suggest as I have always just used the OS defaults regardless of the OS.


Also check to see if macOS added the hidden EFI/ESP partition which will cause problems with other devices.


I believe macOS 12.4 has been released.

Jun 3, 2022 8:52 AM in response to HWTech

That is the Volume's info in Terminal. Allocation sizes that are being utilized are bold.


*********

  Device Identifier:         disk2s1

   Device Node:               /dev/disk2s1

   Whole:                     No

   Part of Whole:             disk2

Volume Name:               UNTITLED

   Mounted:                   Yes

   Mount Point:               /Volumes/UNTITLED

   Partition Type:            Microsoft Basic Data

   File System Personality:   MS-DOS FAT32

   Type (Bundle):             msdos

   Name (User Visible):       MS-DOS (FAT32)

   OS Can Be Installed:       No

   Media Type:                Generic

   Protocol:                  USB

   SMART Status:              Not Supported

   Volume UUID:               F6859688-2C95-316D-89D7-012CF8610D3C

   Disk / Partition UUID:     48754388-6B10-41D7-835B-E138DAB5DB4A

   Partition Offset:          1048576 Bytes (2048 512-Byte-Device-Blocks)

   Disk Size:                 2.1 GB (2061500416 Bytes) (exactly 4026368 512-Byte-Units)

   Device Block Size:         512 Bytes

   Volume Total Space:        2.1 GB (2057461760 Bytes) (exactly 4018480 512-Byte-Units)

   Volume Used Space:         794.6 KB (794624 Bytes) (exactly 1552 512-Byte-Units) (0.0%)

   Volume Free Space:         2.1 GB (2056667136 Bytes) (exactly 4016928 512-Byte-Units) (100.0%)

   Allocation Block Size:     4096 Bytes

   Media OS Use Only:         No

   Media Read-Only:           No

   Volume Read-Only:          No

   Device Location:           External

   Removable Media:           Removable

   Media Removal:             Software-Activated

   Solid State:               Info not available

**********

I am seeing a EFI/ESP partition on the SSD. Could that cause this problem?


********

   Device Identifier:         disk0s1

Device Node:               /dev/disk0s1

   Whole:                     No

   Part of Whole:             disk0

Volume Name:               EFI

   Mounted:                   No

   Partition Type:            EFI

   File System Personality:   MS-DOS FAT32

   Type (Bundle):             msdos

   Name (User Visible):       MS-DOS (FAT32)

   OS Can Be Installed:       No

   Media Type:                Generic

   Protocol:                  PCI-Express

   SMART Status:              Verified

   Volume UUID:               E783267B-A4C3-3556-B751-DBED770EB996

   Disk / Partition UUID:     BEE070BA-6FDC-46A8-9176-EA6763F0B55D

   Partition Offset:          24576 Bytes (6 4096-Byte-Device-Blocks)

   Disk Size:                 314.6 MB (314572800 Bytes) (exactly 614400 512-Byte-Units)

   Device Block Size:         4096 Bytes

   Volume Total Space:        0 B (0 Bytes) (exactly 0 512-Byte-Units)

   Volume Free Space:         0 B (0 Bytes) (exactly 0 512-Byte-Units)

   Media OS Use Only:         No

   Media Read-Only:           No

   Volume Read-Only:          Not applicable (not mounted)

   Device Location:           Internal

   Removable Media:           Fixed

   Solid State:               Yes

   Hardware AES Support:      No

**********


Jun 3, 2022 9:54 AM in response to razvanpopa81

razvanpopa81 wrote:

I am seeing a EFI/ESP partition on the SSD. Could that cause this problem?

The EFI/ESP partition is on the internal drive which is required. The only concern is regarding the USB stick. I cannot tell from the output which partition layout is being utilized. I need to see the output of (disconnect all other external drives and devices which have a "diskX" style identifier so there is no confusion of the drive we are examining):

diskutil  list  external


You should compare the information already provided plus the information about the partition layout from the command I just listed with the working USB stick from the Windows PC and the non-working USB stick from the Mac to see if the partition layouts are different, whether the file allocation sizes used are different, or perhaps the starting block location of the partition is different. Once you know what the working USB stick uses, then you just need to use the macOS command line to attempt to replicate it (probably using the "newfs_msdos" command since it appears to have the most options).



Jun 4, 2022 5:46 AM in response to razvanpopa81

I guess the disk utility in the new MacOS was set by default in GPT, not MBR. Again thanks a lot to all of you.

It's not. If you don't "Show All Devices," it only shows the volumes/partitions on the device. Erasing one of those uses the current partition table on the device. The drive either came with GPT or someone changed it. An extremely large flash device might come formatted with a GPT, but I've never purchased one larger that 32 GB, and they have all been MBR/FAT-32.

disk utility bug in Mac os 12?

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