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I format a flash drive as exFAT on macOS (M1 Pro) but after the format, diskutil list shows the partition as NTFS and it also shows up as NTFS on OpenBSD and Linux. This is strange and I’m not sure what is happening

brokaryote
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1 Answers1

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If the flash drive is using the Master Boot Record partition map, then an ExFAT formatted partition will be given the ID of 7. A NTFS formatted partition is also given an ID of 7. The TYPE column output from the diskutil list command uses character strings to identify IDs. The ID of 7 has been assigned the string Windows_NTFS. This does not mean the partition is necessarily formatted NTFS. In your case, the partition is formatted ExFAT.

Below is part of the output from diskutil list taken from my Mac.

   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:     FDisk_partition_scheme                        +16.0 GB    disk1
   1:               Windows_NTFS MyFlash                 16.0 GB    disk1s1

This output shows the drive has an identifier of disk1 and the ExFAT formatted partition has the identifier of disk1s1. Below is the output from the command fdisk /dev/disk1 which shows the ID is 7.

Disk: /dev/disk1    geometry: 1945/255/63 [31250063 sectors]
Signature: 0xAA55
         Starting       Ending
 #: id  cyl  hd sec -  cyl  hd sec [     start -       size]
------------------------------------------------------------------------
 1: 07 1023 254  63 - 1023 254  63 [         1 -   31250062] HPFS/QNX/AUX
 2: 00    0   0   0 -    0   0   0 [         0 -          0] unused      
 3: 00    0   0   0 -    0   0   0 [         0 -          0] unused      
 4: 00    0   0   0 -    0   0   0 [         0 -          0] unused     

Below is the output from the command diskutil info disk1s1 | grep Personality which shows the partition is ExFAT formatted.

   File System Personality:  ExFAT

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