Another way to fix “The system is running in low-graphics mode” error? [duplicate]

Another way to fix "The system is running in low-graphics mode" error?
[duplicate]

This question already has an answer here:
How to fix "The system is running in low-graphics mode" error? 31 answers
I began having the infamous "system running in low graphics mode" error
after my daughter turned off the power so she could boot into Windows.
Looking at the lightdm log in in /var/log/lightdm/ showed that the greeter
was failing to be created.
The greeter log showed that the greeter could not create its .Xauthority
file.