I had this problem with the 16.04.1 desktop amd64 stick I made on my 14.04 system, but I just had to enter "live" at the prompt to boot into the live desktop and install as normal.
After doing that and booting into the new live system, it was also easy to "fix" the USB stick permanently with the new syslinux available therein, as detailed here: https://askubuntu.com/questions/486602/ubuntu-14-04-lts-live-usb-boot- error-gfxboot-c32not-a-valid-com32r-image/746412#746412 As for the newer version of creator included with 16.04, its behavior was rather unexpected. Instead of copying files into the existing filesystem and installing syslinux nondestructively, it seems to simply write a raw binary image over the first 1.5GB of the disk. It warned me and all, but I didn't see any other option. It didn't have the COM32R error at boot, but I personally feel the destructive copying is much worse. Did I mess something up, or is that the intended behavior now? -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1325801 Title: failed to boot from USB disk with error: gfxboot.c32: not a COM32R Image boot: To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-cdimage/+bug/1325801/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs