starting R: Error: '\U' used without hex digits in character string starting ""C:\U"

Question

I have the following problem when starting RStudio and when I try to compile a PDF from a .rnw format:

Error: '\U' used without hex digits in character string starting ""C:\U"

When starting RStudio or just R, this is what is inside my console:

R version 3.4.0 (2017-04-21) -- "You Stupid Darkness"
Copyright (C) 2017 The R Foundation for Statistical Computing
Platform: x86_64-w64-mingw32/x64 (64-bit)

R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type 'license()' or 'licence()' for distribution details.

R is a collaborative project with many contributors.
Type 'contributors()' for more information and
'citation()' on how to cite R or R packages in publications.

Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.

Global .Rprofile loaded!

Error: '\U' used without hex digits in character string starting ""C:\U"

And this happens when I try to compile a PDF:

Global .Rprofile loaded!

Error: '\U' used without hex digits in character string starting ""C:\U"
Execution halted

This kind of appeared from one day to another, and I am not sure what has changed. I tried updating RStudio and my R version, but it did not help. I am running R on Windows.

How can I fix this issue?

Answer 1

I was able to solve this after all:

I had a section inside my .Rprofile file (in Documents) with "\" instead of "/". So I now changed

# Set mainfolder for PACKAGE package
options(PACKAGE_MAINFOLDER="C:\Users\...")

to

# Set mainfolder for PACKAGE package
options(PACKAGE_MAINFOLDER="C:/Users/...")

and that did the trick.

Answer 2

To make it work, just remove the C:\Users\edmar.campos.cardoso\Dropbox\ and replace all \ with / using the function setwd() to change the working directory in R.

Wrong way:

setwd('C:\Users\edmar.campos.cardoso\Dropbox\...')

Right way:

setwd('/Users/edmar.campos.cardoso/Dropbox/...')

Answer 3

You can use \\ instead of \. This allows skipping from some characters such as \n which is the end of the line or \t which is tab.

Answer 4

For importing files in R, replace the '\' with (two) '\'. Single '\' probably reads it as escape sequence and hence the file path error.