Jan 23, 2015 - I have a WD My Passport for Mac. I used to have a Macbook Air so it would always read the devise cause i guess it was formatted just for Mac. A WD My Passport formatted with Mac file system will be a dud on the Windows and vice-versa. Thankfully, MS-DOS FAT32 and ex-FAT formats have survived to date, and these are the file system to make your WD My Passport work with a Mac and a Windows PC simultaneously.
![Passport Passport](/uploads/1/2/5/6/125607060/668446269.jpg)
Product: WD My Passport Ultra 1TB Operating Systems: Mac & Linux I recently used my WD Passport for a linux system. I formatted this drive in linux to ext4. Now I want to use this drive for my mac again but am having problems formatting this drive using disk utility to hfs. For some reason I can read/write and format this drive fine on linux.
Also when viewing this drive in Disk Utility there are multiple instances of this drive. Unmounting disk Creating the partition map Waiting for partitions to activate Formatting disk5s1 as Mac OS Extended (Journaled) with name Untitled newfshfs: WriteBuffer: pwrite(3, 0x104ae4000, 1048576, 331354112): Input/output error newfshfs: write (sector 647176): Invalid argument Mounting disk Could not mount disk5s1 after erase EDIT #1 Palaeologus helped me find a solution to formatting the drive. Sudo su diskutil list cat /dev/random /dev/diskX Look for the drive and replace X with drive number. Then format drive as FAT. Diskutil eraseVolume ExFAT MyName diskX Once again replace X with disk number. The drive is now assessable.
However I can only format the drive to FAT and not JHFS, formatting to JHFS returns the same error as described at the top of the post.