Helping people with computers... one answer at a time.

We'll look at why you might not be able to add files to a CD-R.

I have just burned music files to a CD-R for the first time, then at a later date tried to add a music file to the same CD-R. I get the message my disk is closed when I try to add a music file at a later time. Is it not possible to add files to a CD-R disk after you have already burned files?

Burning CD-ROMs has gotten easier over time, but it still suffers from some obscure terminology and odd situations. Add to that CD-RW (which is quite different from CD-R), and I can easily understand some confusion resulting.

"When you burn a CD-R you can elect to leave it 'open' - meaning that more files can be added to it."

It depends a lot on the tool you're using to burn your CD-R. I happen to use Roxio's Easy CD Creator, but I've heard good things about Nero as well.

You stumbled on to one of the key terms: closed, sometimes also referred to as "finalized". When you burn a CD-R you can elect to leave it "open" - meaning that more files can be added to it. Often case the default is to "close" the disk, meaning as you've seen, that no more files can be added.

When you leave the CD-R open for more files, the disk space is used slightly less efficiently, and there can be occasional glitches. In researching this article I burned a CD-R in two sessions; I burned a set of files and left the disc "open", and then added another set of files and closed it. In a command prompt it correctly shows that the disk now has around 650 megabytes on it, however Windows Explorer shows it as having only 298, the size of one of the two sessions. All the files are visible in both cases.

My approach to burning CDs has always been to collect up "around" 650-700 megabytes of stuff, and then burn the entire disk in one sitting - closing, or finalizing it. I believe that's the safest, most compatible approach. Multi-session CD-R support was added after CD-R's had started to become popular, and while it works and is convenient, there's still a slight risk that the CD-R might not be readable on all PCs.

And to be clear, CD-R is what's called a "write-once" technology. Once you write to it, you cannot erase what's been written. CD-RW is a Read/Write technology, meaning that you can write, and erase from the media. CD-RW uses a different type of media.

Article C2517 - January 10, 2006

Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

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Recent Comments
34 Comments

I've printed out your instruction for burning CD with Windows XP.When I get to properties/recording.The box that shows up does not have the sharing and recording sections at the top of box.Do you know what I'am missing.I've never saved files to CD drive before.Been using a zip drive.But would like to get the files off the zip drive disks to move them to a new computer I have.Which doesn't have a zip drive.

Posted by: Terry at December 1, 2009 7:20 AM

after writing data for cd/dvd when i put the disk in it always says cd/dvd is full and it is not because it is new never used tried other cd/dvd same message need simplified help

Posted by: winston at December 6, 2009 5:12 PM

I read your article on adding files to CDR. I have been adding files to CDR disks since 2004 using XP's CD Write utility with no problems. I don't remember seeing anything about leaving the disk opened or closed. Now in 2010 I no longer can add files to any of these disks. How can I get this functionality back? I have Nero and it won't let me do it either. It says the disks are read-only.

Posted by: John Hill at August 19, 2010 7:49 AM

This adds to my prior comments. I found that the XP CD Writing wizard uses Roxio software. I checked the properties of the CD drive and found that Recording was not enabled. After enabling recording I found I could add files to CDR's as before. I also didn't see any mention of closing the write session. Somewhere between rebuilding my C: drive and the various Microsoft XP fixes, the record property of the CD Drive got reset.

Posted by: John Hill at August 19, 2010 8:14 AM

thnx a lot for the info.
but i wonder can we still enable the open option iff in case we closed it earlier while burning stuff to our cd??
will it work?

Posted by: Sam at March 3, 2012 4:04 AM
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