Thumb Drive failed to mount after erase

[Mowerman]

I am trying to make a boot drive using a 2Tb thumb drive
I erased & reformatted the drive in disk Utility and got the message

"Could not mount disk3s2 with name ( null ) after erase"
The drive appears in the left panel but the volume is greyed out

Tried terminal "mount" and "mountDisk" with no joy

Any suggestions or have I just proved I know just enough to be dangerous
Machine is a 2011 I-Mac OS is 10.11.6


Terminal session is below


/dev/disk3 (external, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *2.1 TB disk3
1: EFI EFI 209.7 MB disk3s1
2: Apple_HFS 2.1 TB disk3s2
iMac:~ trev$
iMac:~ trev$ diskutil mount /dev/disk3s2
Volume on disk3s2 failed to mount
If the volume is damaged, try the "readOnly" option
iMac:~ trev$ diskutil mountDisk /dev/disk3s2
One or more volume(s) failed to mount

Thanks

 

[StellarVixen]

Maybe it's dead. Do you have another computer to check there?

I had those drives die occasionally, and it resembles situation as yours sometimes.

 

[Mowerman]

Thanks for the prompt reply
I tried disk repair first before resorting to terminal
disk repair says the disk is good.
It mounted before I erased the drive to change the partition map & file system to GUID & HFS+
I have 2 more of these drives and don't want to try another in case I am doing something wrong & destroying them .
IF they are not useable on the Imac then at least I can sell or pass them on to some one else
However I have just tried it in my G5 and it does not mount there either .

IF it add clarity when I tried to partition the disc ( because I did not notice the volume did not mount I got this error message
"The volume “Untitled” is not journaled. As a result it can not be resized. To enable journaling, cancel partitioning and use the “Enable Journaling” command under the “File” menu."
Which is weird because Disk Repair confirms that the system is HFS journaled"
And FWIW "Enable Journaling " is also greyed out

 

[StellarVixen]

Thanks for the prompt reply
I tried disk repair first before resorting to terminal
disk repair says the disk is good.
It mounted before I erased the drive to change the partition map & file system to GUID & HFS+
I have 2 more of these drives and don't want to try another in case I am doing something wrong & destroying them .
IF they are not useable on the Imac then at least I can sell or pass them on to some one else
However I have just tried it in my G5 and it does not mount there either .

It might be still salvageable. Maybe it's just corrupted. I hope someone can definitely tell you what are the options that you have (if there are any).

At least it is still recognized by diskutil so maybe there is hope.

 

[Mowerman]

Not the sharpest knife in the drawer but I do qualify as sane by Einsteins definition of insanity
So the other 2 drives will remain safely on the shelf till I can find what i did wrong