I'm attempting to create a bootable macos installer on a USB pen drive so I can install Mojave on a 2012 MBP while offline. I'm attempting to prepare the USB (and installer) from a different MBP (2015 MBP running Big Sur).

I've followed the steps https://support.apple.com/en-au/HT201372 and the output in terminal reads:

Erasing disk: 0%... 10%... 20%... 30%... 100% 
The erased disk did not mount.

When I check the disk in Disk Utility.app the volume will not mount, and returns the error:

Could not mount “Install macOS Mojave”. (com.apple.DiskManagement.disenter error 49153.)

At this point I'm unable to create/mount a new volume within the UI and have to resort to terminal, such as diskutil partitionDisk /dev/<DISK_NUMBER> MBR <VOLUME_NAME> FAT32 100%. I've also tried other formats, boot records, etc.

Nothing has worked and all roads eventually lead back to the above errors. What can I do?

CodePudding user response：

[face palming] The computer I was trying this on is a company laptop. As it turns out, IT admins have restricted our ability to write to external drives. That was the problem all along. When I tried the same steps on my personal MBP it all worked perfectly as expected.