The testing completed but failed error for chrome

The testing completed but failed error for chrome
Timed out waitng for the browser to start.

I have scheduled wptdriver to task scheduler. Things were working fine. Suddenly, I started getting the above error.

I stopped the scheduled instance and started wptdriver.exe. It works fine.

But I need a scheduled instance working.

Your help is much appreciated

What are the task scheduler options (only when user logs in, what user it runs as, etc)? Also, what OS?