[IceMaiden21]

For the last few weeks, I've been having issues with the audio system. When I first got it, it was working fine.

The radio stations reset to default and CDs start from the beginning (not where they stopped) every time the car starts.

I've checked the memory fuse, it seems to be intact.

Is there anything else that may be causing it??

[Phil №❶]

Is your clock still functioning and maintaining correct time

[CraigB]

Is this the factory installed Hyundai stereo or some after market model?

My factory unit resets itself sometimes when listening to music played via a usb thumb drive, I got sick of it after a while and ended up storing all music on the iPhone instead and played via Bluetooth.
I'm hoping Hyundai will soon release a firmware upgrade that might fix the problem

[IceMaiden21]

I'm pretty sure it's the factory stereo, and the clock has been working fine.

[The Gonz]

I've had the occasional case of the USB overriding my mode selection on ignition. I put it down to the USB you happen to be using.

[Phil №❶]

Do you have someone who will look after your car mechanically 

If you do, ask them to remove the Negative battery terminal for about 30 minutes. This will kill all settings in the car and causes a reset of factory settings in the car's "computer". You will then be required to reset your radio stations again and hopefully, the 30 minute power off will correct your problem.

This fix may or may not work, but no damage to your car can result. If the radio continues it's erroneous behavior, you will have to go to your dealer and see what they can do for you.

[rustynutz]

Just a heads up...
If you follow Phil's advice, just be aware the esp light will stay on. Don't be alarmed, simply drive around the block and then switch the ignition off.
All will be good once you restart the engine... 

[IceMaiden21]

Thanks everyone.
Will give the battery thing a ago and see what happens