If your app uses temporary files, store the file name(s) in the Registry as you create them. When you exit the program, delete the temporary file and its related Registry entry. However, if you shut off the machine, Windows crashes, or your program crashes, your temporary file will stay in the Registry. This leads to wasted space, and you must then delete the files from their temporary directory. Because you stored the temporary file name in the Registry, you can check for it when your program starts up again and delete it if it still exists.