Cannot read configuration file ' trying to read configuration data from file '\\?\', line number '0'

Question

An app pool kept stopping every time it was started and gave this error in the application logs:

The worker process for application pool \'APP_POOL_NA

Answer 1

Wanted to add that this can also manifest if the drive the config file is located on is full. We just found that out today and freeing up space and restarting the application pool fixed it.