During the install process, some random package or part fails to install entirely. It isn't always consistent. Sometimes it's just gcc, other times it's something different. It usually performs a partial install, forcing me to delete the folder and start again.
On my previous install, I tried to get around this by using Pacifist, but even that wasn't 100% reliable, and I could only partially install it instead of just clicking it and installing it like a normal package. If I'm doing something wrong, I have no clue what it is.