Installer offered the folder:
C:\Program Files (x86)\WinSCP\

I decided to install to that folder:
C:\Program Files (x86)\WinSCP\

And got Message box (Abort/Retry/Ignore).

Hit several times Retry and then Abort.

P.S. Also I want to note that I have folder 
C:\Program Files (x86)\WinSCP\
with old version of WinSCP
which was installed to that folder with Administrator privileges in the past.
