Just a quick question to make sure I understand properly: do you mean you tried to install an application while running the ElementaryOS live USB? If so, perhap

Just a quick question to make sure I understand properly: do you mean you tried to install an application while running the ElementaryOS live USB? If so, perhaps that's why it failed? Depending on how the live boot OS is set up, installing new applications may not work at all. Some live USB creator apps I've used give the option of setting aside some space for a writable filesystem that will with with Ubuntu live images (and possibly others). In either case, the best way to get a real sense of how much you like the OS is to do a proper install of it in a VM. The live ISO will mostly just show you if the OS supports your hardware and everything (WiFi, etc.) works.