asks the disk where you want to install mac OS X

Hi Nanajand,

Welcome to Apple Support Communities. We understand that you're having an issue with reinstalling your macOS. We'd like to help.

Are you using macOS Recovery to get this done? Are these the steps you're following? How to reinstall macOS - Apple Support Which macOS are you currently running? It would also be helpful to know which macOS you're trying to install. Let us know so we can determine the best next steps for you.

In the meantime, focus on the other ways to instal to see if that helps:

Other macOS installation options

When you install macOS from Recovery, you get the current version of the most recently installed macOS, with some exceptions:

* On an Intel-based Mac, you can use Shift-Option-Command-R during startup to be offered the macOS that came with your Mac, or the closest version still available. Or you can use Option-Command-Rduring startup to be offered either the latest macOS that is compatible with your Mac, or in some cases the macOS that came with your Mac or the closest version still available.

* If the Mac logic board was just replaced, you might be offered only the latest macOS that is compatible with your Mac.

* If you just erased your entire startup disk, you might be offered only the macOS that came with your Mac, or the closest version still available. 

You can also use these methods to install macOS, if the macOS is compatible with your Mac:

* Use the App Store to download and install the latest macOS or an earlier macOS.

* Use a USB flash drive or other secondary volume to create a bootable installer.

Let us know how that goes.

Take care!