I formatted a USB drive using fdisk, and created three partitions. Everything seems to work fine, but Disk Utility is showing a negative amount of used space for all partitions:

Partition | Capacity | Available | Used | File system

Partition 1 | 5,12 GB | 5,46 GB | -340,8 MB | FAT32

Partition 2 | 12,29 GB | 12,63 GB | -346,2 MB | ExFAT

Partition 3 | 45,33 GB | 45,53 GB | -195,3 MB | HFS+

The drive has a MBR partition table. Switching to GUID is not an option unfortunately.

Is this normal? What can I do to fix this?

Here's a screenshot from fdisk:

Screenshot from fdisk

Thanks in advance!

Edit: Disk Utility also shows an incorrect file count on two of the partitions (P1: 0 files, P2: 374.904 files, P3: 11.068.054 files). All partitions actually contain 0 files.


Apparently it's just a bug in Disk Utility. I re-formatted the stick using multiple other computers, and Disk Utility still displays a negative amount of used space.

I also checked the stick using multiple computers & programs, there are no errors.

Disk Utility is wrong.


I had the same problem after formatting a 8GB pendrive as FAT32 using Disk Utility.

After formatting it was displaying -194MB and would format to any other format after that.

I was able to recover it using the Terminal and the diskutil tool.

First list the current volumes

$ diskutil list

Then format your USB volume

$ sudo diskutil eraseDisk FAT32 MYSD MBRFormat /dev/YourDiskVolume

Here is the output

~ $ sudo diskutil eraseDisk FAT32 USB MBRFormat /dev/disk2
Started erase on disk2
Unmounting disk
Creating the partition map
Waiting for partitions to activate
Formatting disk2s1 as MS-DOS (FAT32) with name USB
512 bytes per physical sector
/dev/rdisk2s1: 15602896 sectors in 1950362 FAT32 clusters (4096 bytes/cluster) 
bps=512 spc=8 res=32 nft=2 mid=0xf8 spt=32 hds=255 hid=2 drv=0x80 bsec=15633406 bspf=15238 rdcl=2 infs=1 bkbs=6
Mounting disk
Finished erase on disk2

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