Reuse Microsoft Office USB stick with 7.9 GB – Error: -69877: Couldn’t open device – dd: /dev/disk9: Permission denied

command linedisk-formatdisk-utilityterminalusb

I have a USB stick from Microsoft, which was used to ship Office 2016 for Mac. I don't use Office 2016 for Mac, so wish to use this stick for other purposes.

/dev/disk9 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:     FDisk_partition_scheme                        *7.9 GB     disk9
   1:               Windows_NTFS Office 2016 for Mac     7.9 GB     disk9s1

> diskutil eraseDisk ExFAT DiskName /dev/disk9
Started erase on disk9
Unmounting disk
Error: -69877: Couldn't open device

> sudo dd if=/dev/zero of=/dev/disk9
Password:
dd: /dev/disk9: Permission denied

> sudo diskutil unmountDisk force /dev/disk9
Forced unmount of all volumes on disk9 was successful

> diskutil eraseDisk ExFAT DiskName /dev/disk9
Started erase on disk9
Unmounting disk
Error: -69877: Couldn't open device

Is this USB stick somehow readonly? How to use it?

Best Answer

The likely answer is that Microsoft has configured this flash drive as read-only to avoid tampering. You'll likely not be able to reuse it for anything else. This is a known practice among certain software manufacturers.