How do I install Sophos AV 9.4.2 for Mac?

Question

I have a 2015 MBP, running 10.11.3. I am trying to install the 9.4.2 version of Sophos AV on it. Just after I authenticate the install, it always errors out thusly : 
 Thinking it might have been a bad download, I re-downloaded the installer and tried again. Same result. Restarted the laptop - same result. Downloaded the Sophos removal tool. Removed Sophos. Restarted. Tried re-installing with the same result. Honestly don't know where to go with this one. I have never had Sophos fail to install on any of my computers before, and the error 'code' is about as generic as can be. Any help deeply appreciated !

1MacGeek · Answer

Will, I am being told that I have an older version of the Sophos for Mac installer. Perhaps I do, but I find it odd I just downloaded that installer last week. Anyway, I am downloading the newest installer, and I will be testing this theory and letting you know how it worked. Even so, I wanted to let you know the latest as soon as I knew it so you could give it a go if you so choose to do so.

WillShen · Answer

In case anyone is still interested, delete /Library/Application Support/Sophos, and try again. It worked for me, finally.