Hide the "Add programs from your network" option: registry value NoAddFromNetworkUserHKCU\Software\Microsoft\Windows\CurrentVersion\Policies\Uninstall

Policy ID
NoAddFromNetwork
Scope
User Configuration
Supported on
Windows Server 2003, Windows XP, and Windows 2000 only
Source
Administrative Templates (.admx) for Windows 11 2026 Update (26H2) (version 1.0)
Category
Control Panel › Add or Remove Programs

Registry

NoAddFromNetwork

-User