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gabriel3374 Author

Level 1

7 points

Cannot erase USB flash drive, "name invalid"

Now, I'll just give the short version of how my problem occurred, continued with a detailed "backstory".

Tried creating bootable USB flash drive with Windows 7.iso on it (kinda worked)
Boot Camp requires flash drive to be formatted "as single FAT partition"
Disk Utility -> Erase -> Error: "Invalid name. Operation failed..."
Terminal -> diskutil reformat /dev/disk2 -> Same Error

Hardware details

- MacBook Pro Mid 2010 with OS X El Capitan

- 32GB SanDisk 3.0 USB flash drive. I had previously installed Linux Mint on it, which worked perfectly.

What I've done to the USB flash drive

For university we could download different versions of Windows for free. So now with a .iso file in my downloads folder I tried creating a bootable USB flash drive using the instructions provided by Ubuntu, because for some reason I found nothing helpful for Windows and figured the commands in terminal wouldn't be much different.

Convert .iso to .img: hdiutil convert -format UDRW -o /Users/me/Downloads/Windows_7.img /Users/me/Downloads/Windows\ 7\ Professional\ N\ with\ Service\ Pack\ 1\ $x64$\ -\ DVD\ $German$/windows_7.iso
Unmount my disk: diskutil unmountDisk /dev/disk2
Initialise (?) disk: sudo dd if=/Users/me/Downloads/Windows_7.img of=/dev/rdisk2 bs=1m
Eject: diskutil eject /dev/disk2

I remember when doing this for Ubuntu, starting up the computer while holding the option key would already give me the option to boot from that flash drive. Sadly didn't work here (only showed my Macintosh as the only option on startup), so I tried using Boot Camp.

What Boot Camp told me

I start Boot Camp, skip "Introduction", on page two I select both the options "Download the latest Windows support software from Apple" and "Install Windows 7 or later version". On another tutorial website I looked up, it showed an extra option to "Create a Windows 7 or later install disk", an option I didn't have.

Note, if I do not select the "Download Windows support software" checkbox, I can't continue because the "Installer Disk cannot be found".

With both checkboxes checked, Continue, it says "Save Windows Support Software" and wants me to select a destination disk. I select my USB flash drive and Boot Camp tells me to reformat my USB flash drive.

What Disk Utility told me

Basic procedure, I thought. Open up Disk Utility -> Select my Flash drive -> "Erase" -> New name, format, "Erase" -> Operation failed.

Come to think of it, "GSP1RMCNPRXFRER_DE_DVD" is quiet a strange name, but that shouldn't be the reason not to reformat it, right? Giving it another name also wouldn't work. I can't rename the device itself on my desktop either. Using another format like "ExFAT" won't work, too. Using the command diskutil reformat /dev/disk2 in terminal gives me a "Name invalid" error, too.

If it's in anyway helpful, that's what the inside of my allegedly bootable flash drive looks like.

Posted on Nov 13, 2015 4:32 PM

49 replies

Loner T

Level 9

59,471 points

Feb 20, 2016 7:39 AM in response to Leonardo Lazo

I picked disk0 as an example. You need to use the /dev/diskN where N points to your 1TB disk.

Feb 20, 2016 7:47 AM in response to Loner T

I got this after trying to run this:

Command (? for help): sudo gdisk /dev/disk2

You may need to edit /etc/fstab and/or your boot loader configuration!

Loner T

Level 9

59,471 points

Feb 20, 2016 8:18 AM in response to Leonardo Lazo

You cannot type Gdisk commands inside Gdisk commands. Press q and go back to Terminal command. Once at the Terminal prompt, run diskutil list and find out which disk is your 1TB disk. Once you know, run

sudo gdisk /dev/diskN (where N is pointing to the 1TB disk).

Feb 20, 2016 8:24 AM in response to Loner T

Did it and here is what I get:

GPT fdisk (gdisk) version 1.0.1

Problem opening /dev/disk2 for reading! Error is 16.

Loner T

Level 9

59,471 points

Feb 20, 2016 12:50 PM in response to Leonardo Lazo

1. Does diskutil list show the disk in the output?

2. Can you mount the disk and test?

Feb 20, 2016 5:13 PM in response to Loner T

I unmounted the disk and mounted it again then I ran:

MacBook-Pro-4:~ Leo_Lazo$ sudo gdisk /dev/disk2

Password:

GPT fdisk (gdisk) version 1.0.1

Caution: invalid main GPT header, but valid backup; regenerating main header

from backup!

Caution! After loading partitions, the CRC doesn't check out!

Warning! Main partition table CRC mismatch! Loaded backup partition table

instead of main partition table!

Warning! One or more CRCs don't match. You should repair the disk!

Partition table scan:

MBR: not present

BSD: not present

APM: not present

GPT: damaged

Found invalid MBR and corrupt GPT. What do you want to do? (Using the

GPT MAY permit recovery of GPT data.)

1 - Use current GPT

2 - Create blank GPT

Your answer:

So which one do I use?

Loner T

Level 9

59,471 points

Feb 20, 2016 5:25 PM in response to Leonardo Lazo

Use option 2 - Create a Blank GPT. Once Gdisk creates a new GPT, use 'p'(rint), 'w'(rite), 'y(es - to confirm the write). Please post screen the output after you execute the commands.

We are going to erase the disk.

Feb 20, 2016 5:28 PM in response to Loner T

Command (? for help): p

Disk /dev/disk2: 1953525168 sectors, 931.5 GiB

Logical sector size: 512 bytes

Disk identifier (GUID): FD5B4614-D6C5-4634-AE82-6BB7B59B95D1

Partition table holds up to 128 entries

First usable sector is 34, last usable sector is 1953525134

Partitions will be aligned on 2048-sector boundaries

Total free space is 1953525101 sectors (931.5 GiB)

Number Start (sector) End (sector) Size Code Name

Command (? for help): w

Final checks complete. About to write GPT data. THIS WILL OVERWRITE EXISTING

PARTITIONS!!

Do you want to proceed? (Y/N): Y

OK; writing new GUID partition table (GPT) to /dev/disk2.

Warning: The kernel may continue to use old or deleted partitions.

You should reboot or remove the drive.

The operation has completed successfully.

MacBook-Pro-4:~ Leo_Lazo$

Feb 20, 2016 5:49 PM in response to Leonardo Lazo

Hi Loner,

After the commands, I did not see the disk mounted. I use the command to mount disk and it said successful but still didn't see. I then rebooted the MacBook Pro and still no disk. So I used Disk Utilities to erase disk again and not all is good.

Thanks so much for all your help. I do have one more question, which is what got me in the first place. Is there a way to actually install Bootcamp & any windows from an external drive and then run windows externally. I do not have a need to use Windows all the time. Honestly only for a few games I like to play every once in a while. That is why I don't want to repartition my internal HD for this.

Thanks again for your help.

Loner T

Level 9

59,471 points

Feb 20, 2016 6:02 PM in response to Leonardo Lazo

You said 'not all good', but I presume you meant 'now all good'. 😉

My recommendation is to create a minimal (40-60GB) Windows installation on the internal disk, and use an external disk as D: (or X: - take your pick) and install all your applications on the external disk. You do not run into licensing issues with Windows being on an external disk. D: could be a 1TB NTFS drive. As long as the external disk is connected with a USB3/TB/FW800 connection, it should perform reasonably well.