Q: El Captain Update Problem

Hi,

Check the startup disk to see if it needs repairing using OS X Recovery.

Startup up your Mac while holding down the Command + R keys.

From there you should be able to access the built in utilities to verify and repair the disk if necessary and restore OS X THEN try upgrading to El Capitan.

Can you boot to Recovery?

About OS X Recovery - Apple Support

- If so you can copy files to an external drive via Terminal in Recovery

Copying Files to External Hard Drive via Terminal?

or you can install OSX on an external drive and then boot to that install and try copying files via FInder

its for my ipod 5th

Maybe, it depends upon the cause of the problem. That is why I suggested a way to recover data if the date is recoverable.

Yes?

The disk titled Macintosh HD is your startup drive. Whether or not you can get data frrom the drive depends on the problem.