I am working with a wix installer and i needed to perform a specific task on uninstall.
  After coding and compiling the msi, I tried to uninstall the product but I got a nasty error saying that the uninstallation cannot continue. The first thing i thought was 'shit, I cannot uninstall it'.
  But here's a solution: MSI copies the original MSI file in the folder:
  C:\WINDOWS\Installer
  and the filename is in the form of 9c2ebd.msi
  You can sort the files by 'Creation Date' if you know when did u install it.
  
  I used then Orca editor to remove the uninstall custom actions which caused the uninstall to be unsucessful.
  Also, another useful to know location is 
  C:\DOCUME~1\[user]\LOCALS~1\Temp
  this is the location where the MSI log are written during installation\uninstallation. sort files by 'Creation Date'to see the log.
