Why won't my Matshita CD-RW CW-8124 burn CDs?

What year model is your Mac...?

see > Identify your iMac model - Apple Support

Is this Matshita your iMac's built-in SuperDrive..?

Try cleaning the SuperDrive with a dry lens cleaning disc.

The Matshita is picky, try using a different brand of blank CD disc's.

Are you trying to burn a music or a data to the CD...?

You can use iTunes or the later Music to burn Music CD's.

You can use Burn as suggested by Kaz-k to burn photo or data CD's.

Also keep in mind that those old SuperDrives were not very durable or reliable.

And that you can use most any aftermarket external USB CD/DVD drive with the iMac.

That drive is over 15 years old with out-of-date firmware and obsolete hardware. Replace with new if you want the burn functionality.

Hi,

Try to burn CDs with following utility, called Burn.

https://burn-osx.sourceforge.io/Pages/English/home.html