A common problem that occurs when burning data into a CD. It happens when the computer is not supplying data quickly enough to the CD writer for it to record the data properly. Recording data to a CD-R is a real-time process that must run nonstop without interruption of the signal. A computer will typically transfer the data to the CD-R faster than it is needed. The CD-R drive stores the incoming data in a buffer as a reserve of data waiting to be written so that minor interruptions or slowdowns in the data flow will not interrupt the writing process. The larger the buffer, the greater the chances of a successful transfer. A buffer underrun error occurs when the flow of data from the original source, such as a hard drive or a CD-ROM drive, was interrupted long enough for the recorder's buffer to empty. The writing action is stopped when this happens, and the recordable disc may be ruined during a write operation.
The most common causes of buffer underrun are out-of-date drivers or a system that does not meet the minimum requirements for CD burning. Before attempting to record onto a CD, check that your CPU and hard drive are fast enough to support CD recording and that your computer has enough RAM and available hard disk space. It is also important to have the latest drivers for the CD-R drive, IDE or SCSI controller.
There are a number of ways to combat buffer underrun errors:
- Defragment your hard drive before writing a CD.
- Copy the data to a local hard drive before writing, but be sure to clear space on the hard drive as the workspace may need to be as large as 650 MB available. It is better to create an image of your source data on the hard drive before writing to a CD.
- Don't burn a CD over a network.
- The flow of data can be interrupted by corrupted files and bad sectors on the hard drive. Run the appropriate scanning software to check for these problems.
- Allow the system to warm up for about an hour before attempting to write a CD.
- Make sure the CD is clean before trying to write it.
- Inferior grade CDs may cause a problem. If the CDs from one particular manufacturer keep failing, try a different brand of disc.
- Try recording at a slower speed, such as 2x.