title: Issue on loading corrupted excel file with R
body: <p>I'm actually trying to import multiple excel files with R but I encounter a problem when I try to load a corrupt one.</p>
  
  <p>My excel files (.xlsm) are in different folders like this : </p>
  
  <p>Machine 
          -- >years 
                   --> months 
                              --> many excel files 
                                            --> load file --> actions on each file</p>
  
  <p>I use multiple sapply function to make a loop and perform some actions with the file datas. Due to corrupt file, the process stops. 
  I tried R functions like file.access() and file_test() but it doesn't help to fix my problem. </p>
  
  <p>What I'm looking for is a function or an embedded shell command which will allow me to know if the actual file is corrupt and then avoid it.</p>
  
  <p>Thanks,
  Thomas.</p>