Cannot mount USB with anything, including Disk Utility I am trying to connect a USB to a Mac I am using, and i cannot seem to.  When i plug the device into the Mac, i get an error that reads 'The disk inserted is not readable by the computer.(It contains an Ubuntu live boot)  This is interesting as i was able to plug it in before and it worked, including when it had those files in it.

I see the usb in the Disk Utilities menu, but when I click 'mount', it does nothing to it, and when i try to verify it, it says to repair the disk, but that option is blanked out.  When I try to clear the USB of the files, it says that it can't connect to the device.

Is there any way i can mount or access the device so that i can copy files to this?  I can't use another USB as i don't have another one to use for this.
I'm guessing the drive is in a filesystem that is either not supported by Mac or corrupted. First, you should connect the drive, open Terminal and type

diskutil list


Then you'll see a few disks (shown similar to /dev/disk1) and their name and size. Based on their name/size, locate which one is the problematic drive and edit your question to include it's entry.

But either way, the case is probably that the drive is just not formatted so good. Mac can be really picky sometimes when it comes to disks, so I really recommend you try to burn the ISO onto the drive using Rufus. Rufus is an incredible tool which is also completely free, but unfortunately it's only available for Windows. So try to get yourself one (or maybe ask a friend to allow you to use his) so you can use this tool, then just open Rufus, choose your disk in the drop-down menu (make sure you choose the right disk!!), check the box saying "Create bootable disk" and click the disk button, choose you ubuntu ISO, and hit format. I use Rufus a lot and it hasn't failed me yet.