Startup Disk Creator fails to install bootloader.

What OS are you using to make the bootable USB stick?
What tool/method are you using to put the data onto the storage?

The OS was Ubuntu 14.04.2 on my laptop (Dell Vostro 1510 with 4GiB ram and 250G hard drive) using the Ubuntu's Startup Disk Creator. The intention was to update another machine to Ubuntu 15.04 ready for Ubuntu 15.10 later this month. I did use the DVD path in the end but thought I should raise the problem as it could prevent me testing the next LTS (Ubuntu 16.04) pre-release versions without creating lots of DVDs that will normally only get used once.
A thought occurred that it could be it is looking for a root password different to the sudo user password and thus blocking it.

if you run the startup disk creato with gksudo it will run as root
In Ubuntu, there is no root password

I wasn't using using the command line but the graphic desktop interface, it does require the user password to install the bootloader onto a USB stick but in the past it is my normal login administrator (sudo) password that I have used before, I've not changed the password so something else has changed, I don't know why it doesn't work. My thought was if the current version has been changed it might explain it otherwise it must be the USB stick somehow preventing the software from loading the bootloader, unlikely because the USB stick has been used to install software before and not had the same problem.

Do you use autologin or do you have to type your password to log in to the system?

I have always had to use a password to log in, I only ever tried a system in VirtualBox without a password log in when I was using Windows Vista Business which itself required a password, (a system long since removed), so password log in has always seemed normal (as was the Unix system where I used to work).

You can configuere autologin (as you know). The password to authenticate when you use sudo is the same password you use when you log in.

The laptop has always required a password to log in, and the same password is that one in this case. I can only assume the USB reformat doesn't set it to "bootable" even when the flag is set (checked with both Disks software and GParted).
Is there an alternative to the "Startup Disk Creator" that I could try?

This question was expired because it remained in the 'Open' state without activity for the last 15 days.

This problem is persisting with Ubuntu 14.04.3 on my laptop but I have not tried to use the USB Creator on Ubuntu 15.10 yet. I had to create a DVD to install it on the desktop I have.

John

I have solved this problem I think, not being able to create a bootable USB installer using USB sticks I had used before and having a working USB installer (an old OS version) I tried investigating the USBs with the problem. It seems they had been reformatted to FAT16 with some odd partitioning. I wiped one clean with fdisk and made it FAT32 and it then installed the bootloader and was bootable using Ubuntu 15.10 to create a new copy of the 14.04.3 ISO that was failing to install the bootloader before.
It may be normal but the USB Creator doesn't seem to work on FAT16 formatted USBs. Now I have to find what program changed the the USB format, I thought FAT32 was normally the default these days.