Installer crashes when wiping disk

[Jerry Han]

I tried to install Ubuntu 18.04 LTS, but when I get to the point where the installer warns me about something with mount points, right after selecting wipe disk from the menu of:
Wipe Ubuntu 16.04 LTS Files
Install Alongside Ubuntu 16.04 LTS
Wipe Disk and Install

I selected wipe disk, and was met with a warning. I clicked continue, and then the installer crashed, leaving me in a small part of Ubuntu, where I have the desktop, time, and battery status, as well as Firefox, but nothing else. I am sort of new to Ubuntu, so I don't know what to do with my USB stick, or the half running Ubuntu that I am stuck in now.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: ubiquity 18.04.14.12
ProcVersionSignature: Ubuntu 4.18.0-15.16~18.04.1-generic 4.18.20
Uname: Linux 4.18.0-15-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.5
Architecture: amd64
CasperVersion: 1.394
CurrentDesktop: ubuntu:GNOME
Date: Wed Mar 27 23:03:29 2019
InstallCmdLine: file=/cdrom/preseed/ubuntu.seed boot=casper initrd=/casper/initrd quiet splash --- maybe-ubiquity
LiveMediaBuild: Ubuntu 18.04.2 LTS "Bionic Beaver" - Release amd64 (20190210)
ProcEnviron:
 LANGUAGE=en_US.UTF-8
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 LC_NUMERIC=C.UTF-8
SourcePackage: ubiquity
UpgradeStatus: No upgrade log present (probably fresh install)