Turning on the Windows 10 feature "Windows Sandbox" fails and throws an error (0x800F0922)

When trying to turn on the Windows Sandbox feature, the installation fails and throws 0x800F0922 with no concrete error message, it just says:

The changes couldn't be completed. Please, reboot your computer and try again.

Of course, I've tried it, but it didn't help.

There's a hyperlink pointing to the "appropriate" page on Microsoft.com Support, where the error should be described. The steps that are provided, cannot be done because of a very simple reason: they say:

1. Open the .NET Framework installation files folder.
2. Open Sources folder
3. Right-click the SXS folder, and then click Properties.
4. etc.

There's no Sources folder, nor an SXS folder inside the .NET Framework installation files folder (C:\Windows\Microsoft.NET\Frameworkor C:\Windows\Microsoft.NET\Framework64) or the sub-folders (the different .NET versions). I even created the two missing folders manually to try these steps.

Do you know why I cannot install the Windows Sandbox feature and why I get this error code? I thought it is because I use Docker (on my PC) and they are somehow conflicting with each other, such as Docker and VMWare (when you enable virtualization from BIOS). But I use Docker on my laptop as well. And I could install Windows Sandbox on my laptop. Both my PC and Laptop have Windows 1909 installed.

Additional information:

1. Hyper-V is enabled on my PC
2. I turned off "Controlled folder access" from within Defender and tried (it didn't work).

This is mainly caused by the damage of the .net framework features. You can uncheck .net framework 3.5, .net framework 4.8, hyper-v and windows sandbox features in windows features. Then reboot your computer and check all the 4 features on again. Windows will automatically download needed files and fix there 4 features. Then reboot as required and windows sandbox will be enabled. Hope this works for you.