The Ubiquity installer crashes a few seconds after the partition stage.
If you have this problem, then you are experiencing Bug #1751252. I know the issue is meant to happen on XPS 9560 and the errors aren't the same but I fixed it using the same patch.
Before you begin, make sure you do all the partitioning BEFORE opening the installer.
Then I used the patch from the answer below, copied from this question.
...there is a patch you can use as a workaround...
- Boot your 18.04 Live ISO
- Select Try Ubuntu
- Before you start the Ubiquity installer, open a Terminal window (CTRL-ALT-T)
Execute the following commands in the Terminal to download and apply the patch
cd ~/Downloads wget https://code.launchpad.net/~azzar1/ubiquity/+git/ubiquity/+merge/345056/+preview-diff/831305/+files/preview.diff --output-document ubiquity.patch sudo cp /usr/lib/ubiquity/ubiquity/misc.py /usr/lib/ubiquity/ubiquity/misc.py.original sudo patch /usr/lib/ubiquity/ubiquity/misc.py ubiquity.patch
Start the installer by clicking on the Ubiquity icon, and it should now allow you to proceed through the installation