Since the 7th of February all my tests are failing with the same error; the log entry reads:
RESPONSE MaximizeWindow unknown error: cannot get automation extension
from unknown error: page could not be found: chrome-extension://aapnijgdinlhnhlmodcfapnahmbfebeb/_generated_background_page.html
(Session info: chrome=57.0.2987.21)
I'm not sure if this is caused by a Chrome update or something else - the message is vague enough as it is.
EDIT: I am using C#, and the latest Chromedriver.
You need the latest version of chromedriver.exe. https://sites.google.com/a/chromium.org/chromedriver/downloads
This is needed for chromedriver version 57+
I was having this same issue. Once I updated the chromedriver version everything worked again.