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>
I've been having the exact same problem. I tried to make USB Live with YUMI and Unebootin with the same error mistake:

SYSLINUX: No DEFAULT or UI configuration directive found!

I've tried to

1. change isolinux etc to syslinux (by copy paste, so there's no spelling mistake)
2. format USB to FAT16 instead of FAT32
3. format USB to FAT16 instead of FAT32 and renaming those files (copy paste)

all failed.

Then I tried to use [Universal USB Creator](http://www.pendrivelinux.com/universal-usb-installer-easy-as-1-2-3/) (same as YUMI but Windows version), and it works!

Just giving alternative suggestions if all you tried failed!