Comment 3 for bug 1499746

I am the "another user" Nio mentions above. To confirm, in my case the bug appeared two days ago when attempting a 64 bit 15.10 startup disk under 64 bit 15.04. I attempted this process on three different USB devices: a Transcend 16Gb, a SanDisk Cruzer 4Gb and a Lexar USB Card Reader with a Transcend 4Gb Micro SDHC card in it.

There were no error messages during the usb-creator-gtk session, just an unbootable USB stick as a result.

I should mention that I had to erase the sticks with the Ubuntu "disks" utility as the "erase disk" function in usb-creator-gtk would not clear the drive for me, giving me the message:

org.freedesktop.DBus.Python.GLib.Error: Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/dbus/service.py", line 707, in _message_cb
    retval = candidate_method(self, *args, **keywords)
  File "/usr/share/usb-creator/usb-creator-helper", line 275, in Format
    block.call_format_sync('vfat', GLib.Variant('a{sv}', {'label': GLib.Variant('s', '')}), None)
GLib.Error: udisks-error-quark: GDBus.Error:org.freedesktop.UDisks2.Error.Failed: Error synchronizing after initial wipe: Timed out waiting for object (0)

The "disks" utility has no problem formatting my usb sticks; usb-creator-gtk shows no errors (as I noted above) installing the system on the drive so formatted.

Also I was able to create a working boot disk on the Transcend 16Gb using unetbootin.