Or, you may also conduct a media check prior to burning the ISO, from the command line as follows: sha1sum /[path]/[to]/[ydl].iso [ENTER] ... which will output a SHA1SUM which you compare against the SHA1SUM in the SHA1SUM file. To check your media from Windows, select one of the tools mentioned here: http://www.labtestproject.com/win/sha1sum.exe.html To check your media from OSX, follow the instructions posted here: http://www.bresink.com/osx/sha1.html