Q: i´m trying to reinstall OS X and my sister are taking over my laptop but she can't install OS X because it says "Object is not available for now" "try again later". What can we do?

Hi there simonblabla,

I understand that you are trying to complete your due diligence before giving your computer to your sister, but are running into some issues. I would like to suggest that you first use Disk Utility in order to verify and repair your disk:

Using Disk Utility to verify or repair disks - Apple Support

https://support.apple.com/en-us/HT201639

You may also want to follow the steps in this article about reinstalling OS X on your Mac:

How to reinstall OS X on your Mac - Apple Support

https://support.apple.com/en-us/HT204904

The information in that article could also be used to point out exactly where in the process the error is happening. Finally, the full list of things you will want to do before giving away your computer can be found here:

What to do before selling or giving away your Mac - Apple Support

https://support.apple.com/en-us/HT201065

Thanks for being a part of the Apple Support Communities!