What's a 'UDF' formatted CD? by Leo A. Notenboom UDF format is simply just another way that CDs can be written. What’s a ‘UDF’ formatted CD? ISO 9660 is the standard for CD’s that has been used for many years defining how CD’s are witten. UDF (Universal Disk Format) came along with DVDs and is being used on other media as well. Become a Patron of Ask Leo! and go ad-free! I found this article: Which DVD / CD format: ISO or UDF? that explains in a little more detail. Subscribe to Confident Computing! Tech problem solving & safety tips & a weekly confidence boost in your inbox every week. I'll see you there! Slow Computer? Speed up with my special report: 10 Reasons Your Computer is Slow, now updated for Windows 10. NOW: name your own price! You decide how much to pay -- and yes, that means you can get this report completely free if you so choose. Get your copy now! Related Posts How Do I Reactivate an Old Email Account? - A closed email account is either waiting for you to reactivate it, or is closed for good. The only way to tell is to try. What Security Software Do You Recommend? Basic Protection in Four Steps - My recommendations for specific security software and techniques to keep your computer, and yourself, safe. How Do I Change the Startup Order in Windows 10? - Changing the order of Startup items in Windows isn't supported. Any techniques to attempt to do so are risky and error prone. Five Steps to Better Security Working from Home - Security threats for people working from home are increasing. I'll review steps you need to take to keep yourself, your company, and your job safe.