Microsoft blocking install of LibreOffice?

Hi, I did two installs today of LibreOffice on two separate machines, one an old Vista x86 machine and the other a Win7 64bit. The LibreOffice installer would not run until I went into it’s properties and clicked “Unblock”. The text that explained the reason for blocking it was as follows: First a label that said “Security” and then “This file came from another computer and might be blocked to help protect this computer”.

How long has this been going on? I know it doesn’t happen with any other software that I use that is a competitor of Microsoft.