I get an error "Steinberg Library Manager is not present..."

I bought cubase 12 update (from ver. 11 for windows 11) software. However, the main setup software does not install properly on Steinberg Download Assistant software. So, when I unzipped the .zip in the /win64/Cubase Pro 12.0.40 folder and run setup.exe
but I get an error “Steinberg Library Manager is not present…”
So I removed Steinber Library Manager and re-install it(of course, I re-installed the latest version. but the same error occuered.
How can I install Cubase 12 software properly?
I need help.

Hi and welcome to the forum,

I would try to instal Steinberg Library Manager as the administrator and then I would start Cubase installation also as the administrator.