loading a large file using fread()

[Quack]

I am trying to load this 2360148 character file

library(data.table)
twitter <- fread('C:/Users/mlrob/Documents/en_US/en_US.twitter.txt')

the message from the console
Error in fread("C:/Users/mlrob/Documents/en_US/en_US.twitter.txt") : 
  File 'C:/Users/mlrob/Documents/en_US/en_US.twitter.txt' does not exist or is non-readable. getwd()=='C:/Users/mlrob/OneDrive/Documents'

I try to 

setwd("C:/Users/mlrob/Documents/en_US")

Only to get this message:
Error in setwd("C:/Users/mlrob/Documents/en_US") : 
  cannot change working directory
How can I fix this?  Thank you.

[nwerth]

Does the "C:/Users/mlrob/Documents/en_US" directory exist? If you copy and paste that into the Windows file explorer, does it take you to where you want?

What I mean by copy-pasting it:

Once you've pasted it, hit Enter.