Update install-win10.md

Author: mattwojo

WSL/install-win10.md

@@ -52,7 +52,9 @@ wsl --set-default-version 2
 You might see this message after running that command: `WSL 2 requires an update to its kernel component. For information please visit https://aka.ms/wsl2kernel`. Please follow the link ([https://aka.ms/wsl2kernel](https://aka.ms/wsl2kernel)) and install the MSI from that page on our documentation to install a Linux kernel on your machine for WSL 2 to use. Once you have the kernel installed, please run the command again and it should complete successfully without showing the message. 
 
 > [!NOTE]
-> The update from WSL 1 to WSL 2 may take several minutes to complete depending on the size of your targeted distribution. If you are running an older (legacy) installation of WSL 1 from Windows 10 Anniversary Update or Creators Update, you may encounter an update error. Follow these instructions to [uninstall and remove any legacy distributions](https://docs.microsoft.com/windows/wsl/install-legacy#uninstallingremoving-the-legacy-distro).
+> The update from WSL 1 to WSL 2 may take several minutes to complete depending on the size of your targeted distribution. If you are running an older (legacy) installation of WSL 1 from Windows 10 Anniversary Update or Creators Update, you may encounter an update error. Follow these instructions to [uninstall and remove any legacy distributions](https://docs.microsoft.com/windows/wsl/install-legacy#uninstallingremoving-the-legacy-distro). 
+>
+> If `wsl --set-default-version` results as an invalid command, enter `wsl --help`. If the `--set-default-version` is not listed, it means that your OS doesn't support it and you need to update to version 2004, Build 19041 or higher.
 
 ## Install your Linux distribution of choice