> For the complete documentation index, see [llms.txt](https://docs.parallels.com/landing/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.parallels.com/landing/pdfm-ug/parallels-desktop-for-mac-27-users-guide/advanced-topics/working-with-virtual-machines/setting-guest-os-type-and-version.md).

# Setting Guest OS Type and Version

You can change which guest OS a virtual machine is configured to work with. You need to change it in the following cases:

* If you upgrade the guest operating system (for example, from Windows 10 to Windows 11), you need to change the guest OS type and version correspondingly, or [Parallels Tools](/landing/pdfm-ug/parallels-desktop-for-mac-27-users-guide/advanced-topics/installing-and-updating-parallels-tools.md) may start working incorrectly.
* If you create a virtual machine without installing an operating system, and then decide to use it with a different operating system than the one you initially specified.

To set the guest OS type and version:

1. [Shut down the virtual machine](/landing/pdfm-ug/parallels-desktop-for-mac-27-users-guide/use-windows-on-your-mac/getting-started/shutdown-and-suspend-windows.md).
2. Open the **Actions** menu and choose **Configure**.
3. Click **General** and select an OS from the menu just above the **Name** field.


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