title: I get 'Error: '\U' used without hex digits in character string starting ""C:\U"' when starting R
body: <p>I have the following problem when starting RStudio and when I try to compile a PDF from a .rnw format:</p>
  <pre class="lang-none prettyprint-override"><code>Error: '\U' used without hex digits in character string starting &quot;&quot;C:\U&quot;
  </code></pre>
  <p>When starting RStudio or just R, this is what is inside my console:</p>
  <pre class="lang-none prettyprint-override"><code>R version 3.4.0 (2017-04-21) -- &quot;You Stupid Darkness&quot;
  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 &quot;&quot;C:\U&quot;
  
  And this happens when I try to compile a PDF:
  
  Global .Rprofile loaded!
  
  Error: '\U' used without hex digits in character string starting &quot;&quot;C:\U&quot;
  Execution halted
  </code></pre>
  <p>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.</p>
  <p>How can I fix this issue?</p>