title: WiX - VC++ Runtime - vcredist vs merge module
body: <p>I am building a MSI installer using WiX. As the product that is supposed to be installed requires a VC++ runtime I found the two option of doing that which are (a) using the corresponding merge module and (b) using burn to run vcredist prior to the actual product's MSI. To differ between those two options I have some questions I didn't find the information on.</p>
  
  <p>1) If using the merge module the runtime is not installed separately (no entry in add and remove programs) but as far as I understand just copies the required files to their corresponding locations.</p>
  
  <p>1.1) If there already is an installation of vcredist present on the system I suppose the merge module does nothing during the product's installation?</p>
  
  <p>1.2) If there was a vcredist installation present as mentioned in 1.1) what happens if the user just uninstalls that runtime via add and remove programs? I suppose the product does not work anymore (at least until a repair installation is performed which causes the merge module stuff in the MSI to re-add the necessary files?)</p>
  
  <p>1.3) If the vcredist was not yet installed and the MSI installer copies the files to the system and after that another installer or the user is calling the vcredist.exe what is happening then? Does vcredist reports the runtime as already being installed?</p>
  
  <p>1.4) If uninstalling the product are the files copied to the system via the merge module being removed?</p>
  
  <p>1.5) If the answer to 1.4) yes (VC++ runtime files are removed): If there are two different products are installed on the system both using the same merge module internally and one of the two products is uninstalled what happens to the installed runtime files? Are they removed and the other product is not working anymore due to the missing runtime files?</p>
  
  <p>Thanks in advance for your help and information.</p>
  
  <p>Regards,
  Gunnar</p>