Question: I have a USB live key created with Linux Live USB creator. I used all the defaults, and got a standard version of Ubuntu. When I try to boot into it, I get the error above. I went through the rest of the threads with no avail.

Things I tried:

* Renaming the files (my files were already syslinux.cfg, etc.)
* Typing in `mboot.c32 -c boot.cfg` into the boot:\_\_ prompt

Any help would be appreciated!

Answer: 
**General answer**

Generally the iso image that are intended to be burned and booted from CD/DVD has all the files required for boot in the `isolinux` folder. Whereas the iso images that are intended to be run from USB has all the files required for boot in the `syslinux` folder. So when you try to burn and boot a CD/DVD iso from USB, it cannot recognize the type of boot medium as it will not have `syslinux` folder it will simply give `Boot failure : No DEFAULT or UI configuration directive found!`.

**General solution for the Error**

Open the USB installation media, then rename the following:

```
isolinux –> syslinux (folder)
isolinux.bin –> syslinux.bin
isolinux.cfg –> syslinux.cfg

```

The system looks for these two files (.bin & .cfg) in the `syslinux` folder at root of the device. So make sure you have both files in the `syslinux` folder.

* source: <http://www.geekzground.com/index/?p=27>
* same: <http://techie-buzz.com/how-to/syslinux-no-default-ui-error-fix.html>
* <http://www.syslinux.org/archives/2010-October/015756.html>
It seems for everyone it has a different solution, for me, the solution was to format my Flash drive with the FAT filesystem and make a boot drive with the Universal USB installer and voila, worked like a charm.