does samsung magician show ahci disabled with signed driver error on

ARC1020 said:

The OP's question refers to"after clean install".

In April 2015 Microsoft told everyone that all new Windows 10 Kernel mode drivers needed to be signed with an EV Code Signing Certificate and then submitted to the Windows Hardware Developer Center Dashboard portal to be signed in order for them to work.

This policy was enforced in the Anniversary Update starting with new installations of Windows 10, version 1607. Clean installations of Windows 10, version 1607 will not load any new kernel mode drivers which are not signed by the Dev Portal. I.E. If the OP is getting driver signing errors after a clean install, then Samsung haven't complied with the driver signing requirements (which they have known about for over a year).

Microsoft changed Driver Signing Requirements:
Driver Signing changes in Windows 10, version 1607 Windows Hardware Certification blog

MS is also going to be coming out with more updates to fix some of the issues that the Anniversary update, has caused so many people. Already had 2 .....maybe 3, as I've lost count. More to come. :)

Enforcement only happens on fresh installations, with Secure Boot on, and only applies to new kernel mode drivers:

• PCs upgrading from a release of Windows prior to Windows 10 Version 1607 will still permit installation of cross-signed drivers.
• PCs with Secure Boot OFF will still permit installation of cross-signed drivers.
• Drivers signed with an end-entity certificate issued prior to July 29th, 2015 that chains to a supported cross-signed CA will continue to be allowed.
• To prevent systems from failing to boot properly, boot drivers will not be blocked, but they will be removed by the Program Compatibility Assistant. Future versions of Windows will block boot drivers.

Maybe try uninstalling Magician, turn of secure boot in BIOS, reinstall Magician, make sure it's working properly, then turn on secure boot again to see if he can get it to work that way? If not, then one needs to decide which is more important, a basically unneeded software(I only have it for firmware updates) or Rootkit protection.