Disable your antivirus and disconnect from the internet temporarily to ensure the installer isn't flagged.
Let’s be clear upfront: This is not an official Steinberg release. Steinberg never sold a "Win7 Edition" of Cubase 5.1.2. This is a piece of . steinberg cubase 512 proper win 7 edition antony grl install
The original Cubase.512.Proper.Win7.Edition-ANTONY came in RAR archives split into 47x15MB files. Inside the main folder, you would find: Disable your antivirus and disconnect from the internet