Can't format My Passport for Mac external drive

On my MacBookPro (Snow Leapord OS) I have run the disk utility to erase and format this drive but I get the following message:

“Disk Erase failed with the error: POSIX reports: The operation couldn’t be completed. Cannot allocate memory”

I also tried to Partition the drive but got the same error. I want to use this external drive for cloning my system HDD and thought that reformatting the drive would be advisable before proceeding.


Richard (Pinawa)


I have the same problem. I was using the 500G ‘My Passport’ USB for time machine backups. I can’t even format it on a Windows computer using the format /fs:ntfs (or Fat32) command. It just sits at 0% completed.


I had this problem before as well. I was able to format the drive once connected to another computer (preferably windows) and then retrying on the MAC. You can also format using the OS X CD.