User Tool Tips: Bulk rename file extensions in Window 10

  1. in explorer, navigate to the folder with the files to rename
  2. click in the address bar and type cmd and press enter
  3. it should then open cmd prompt to the current folder
  4. in the command prompt window verify you are in the correct directory
  5. type the following then press enter
  6. rename *.old *.new
  7. all of the .old file names should now be .new
  8. close the command prompt