From your comments above, it looks like you did a complete install of Ubuntu on the 16GB USB drive.
There are two methods to put Ubuntu in an USB. The first is a LiveUSB that is used to install Ubuntu in the hard drive. The second is a full install, where the USB works like a hard drive. See What would be the differences between a persistent USB Live Session and a installed Ubuntu in a USB drive?
A full install on a 16GB USB, formatted the USB drive ext4
. This is the format Ubuntu (Linux in general) requires. Ubuntu cannot be installed in NTFS
. The ext4
partition where Ubuntu is installed cannot be changed to NTFS
. If you do, you will lose all the ownership and permission information Ubuntu needs to work properly. Then Ubuntu won't work.
On the other hand, Windows does not know about ext4
format and thus can't read.
Solutions:
There are third party extensions you can install in Windows to make it read ext4
partition. See 3 ways to access your Linux partition from Windows.
Alternately, recreate the USB drive.
You can create a small (say 512MB) FAT32
partition in the beginning of the USB drive to share some data. This should be the first primary partition partition for Windows to see it. You can leave the rest of the 16GB unallocated for Ubuntu installation to find it. Or you can choose "Something else..." during Ubuntu installation and format the remaining part of the drive ext4
and select mount-point /
.
Hope this helps