kmosx: Unable to read the contents of a CD!

Mac OS X cannot read my CD ! Did I do something wrong ?

Although this is very uncommon, some users may be unable to read a CD or a DVD on their computer. This FAQ explains why and provides some step-by-step troubleshooting instructions and tips.

I - The hardware tests

Is the CD clean ? Keep in mind that CDs may be easily damaged by dust, scratches or fingerprints. A slightly damaged CD may become unreadable, cause the CD drive to make some excessive noise or prevent Mac OS X from reading its contents quickly enough to provide a real-time browsing experience.

Therefore, it is important to make sure that the CD is perfectly clean. Even unnoticeable alterations can damage its surface depending on where they are located on the disk and on the quality of the coating. Follow carefully the cleaning instructions provided by the disk's manufacturer if needed.

As a general rule, do not use any abrasive products or cloths. Would you put water or any product on the CD, make sure that it is perfectly dry and that there are no residues on it before inserting it into your optical drive.

Is the CD non-standard ? Although some Mac are able to read non-standard discs, you should always check wether your drive is compatible with them before using them. A very detailed list of discs, formats and drives may be found on this page.

Is the CD correctly inserted ? Although this may sound silly, make sure that the CD is inserted in the right way. As a general rule, the � printed � side of the CD should be up. Some modern CDs have two readable sides - or at least, two sides that look the same.

II - The software tests : Music CDs

Would you encounter issues with a music CD, keep in mind that some of them are copy-protected and cannot be inserted in any computer - Macintosh or PC... Usually, such CDs are clearly labeled. Check for notes like � This CD cannot be read by a Mac or by a PC �, � This CD shouldn't be used on a computer �...

Do not attempt to insert such copy-protected CDs in your optical drive : you may be unable to eject them normally and, under some very rare circumstances, they may damage your drive.

As a general rule, always do make sure that your driver's firmware is up-to-date : firmware upgrades may prevent issues or add functionalities to your drive. For example, you may want to check this link.

III - The software tests : home-made CDs

Would you try to read a burnt CD - CD-R or CD-RW -, it is possible that the CD in itself is faulty. Did you check the CD after you first burnt it ? Does your burning software check the integrity of the data once the process is completed ? You may want to ask the person who gave you the CD to check it or to burn another one.

Would you use a colored CD, make sure that it is compatible with the drive. Some drives may accept blue, purple or green discs while some others cannot read them and will eject them automatically. Would you burn a CD - or a DVD - for a PC user, make sure that their drive is compatible with the format that you are using : Mac Combo drives and Super Drives are compatible with a very wide range of formats...

IV - Mac & PC compatibility issues

You may experience issues while sharing discs between PCs and Macs. This does not mean that Mac OS X is faulty or that it isn't compatible with PC disks. However, many disk formats are available : Mac OS X and PCs share most of them but it is worth checking before sending a CD...

The PC user you are trying to send a CD to may use an old computer with an old drive... In that case, should you send a CD-R or a CD-RW ? Ask which format is better !

Do you want to provide feedback on this User Contributed Tip or contribute your own? If you have achieved Level 2 status, visit the User Tips Library Contributions forum for more information.

It may be worth reading this Knowledge Base article : it provides detailed information about CD formats. Would you need to burn some special CDs with special formats, you may want to use a third-party burning application. You may want to check the Apple Store for more information about them.

V - Help ! It is too late !

Would a CD be stuck in your optical drive, here is a way to force-eject it. Users who are not comfortable with Open Firmware may simply want to restart the computer while holding the mouse - or trackpad - button down : in most cases, this will also eject the CD.

For your own safety, do not try to open the optical drive by yourself or to eject a CD by using tools - a screwdriver, for example... Check the manual that came with your computer !

This basic troubleshooting tips should solve issues in most cases. Of course, would you have any additional questions, do not hesitate to post on the forums ! We would all be very glad to help you !

Tip : before posting in the forums, make sure that you browse both the Mac OS X forum and the hardware forum related to your computer. Chances are that an easy answer is already waiting for you, in an archived thread.