Windows 11 in S mode is designed for security and performance, exclusively running apps from the Microsoft Store. If you want to install an app that isn't available in the Microsoft Store, you'll need to switch out of S mode.
Windows 11 in S mode is only available in the Windows 11 Home edition. If you have the Pro, Enterprise, or Education editions of Windows 10 in S mode, Windows Update will not offer Windows 11 because S mode is not available in those editions of Windows 11. Therefore, if you have the Pro, Enterprise or Education editions of Windows 10 in S mode, you'll need to switch out of S mode to upgrade to Windows 11.
Switching out of S mode is one-way. If you make the switch, you won't be able to go back to Windows 10 or Windows 11 in S mode. There's no charge to switch out of S mode.
On your PC running Windows 11 in S mode, open Settings > System > Activation.
In the Switch to Windows 11 Pro section, select Go to the Store. (If you also see an "Upgrade your edition of Windows" section, be careful not to click the "Go to the Store" link that appears there.)
On the Switch out of S mode (or similar) page that appears in the Microsoft Store, select the Get button. After you see a confirmation message on the page, you'll be able to install apps from outside of the Microsoft Store.
System Requirements (Students)
Windows: 11, and 10*
* Includes x86 32 and 64bit processors and ARM 64bit processors using x86 emulation.
* Windows 10/11 "S mode" is not a compatible operating system, nor can LockDown Browser be obtained via the Windows App Store. At present, support for Windows 10/11 "S Mode" isn’t on the roadmap for LockDown Browser.