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USB Thumb Drive Won't Do HFS+ Format

markbyrn asked
Last Modified: 2012-05-11
I've been trying to format a 128 GB USB thumb drive as a Mac OS Extended volume (HFS+) but it silently fails and the only successful format I can do is MS-DOS FAT. As I want to use the drive to install a dev version of Lion, I need the HFS+ format and trying it in terminal gave the following result:

Marks-MacBook-Pro:~ markbyrn$ diskutil eraseDisk HFS+ lion disk1
Started erase on disk1
Unmounting disk
Creating the partition map
Waiting for the disks to reappear
Formatting disk1s2 as Mac OS Extended with name lion
Initialized /dev/rdisk1s2 as a 128 GB HFS Plus volume
Mounting disk
Could not mount disk1s2 with name (null) after erase
Finished erase on disk1
Marks-MacBook-Pro:~ markbyrn$

So it appears to initialize but won't mount. I also tried partioning the drive into 2 or 4 partitions and formatting an individual partition but that didn't work either.

I have installed the dev version (preview 2) of Lion on a 16 GB thumb drive but there's not enough free space to do an update to preview 3. Any advice on how I can get this 128 GB thumb drive formatted?
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