"This scan has never been completed"

I have been using Sophos (the Home for Mac version) but within the last few weeks it seems the scans are not completing. (This is preventing me from connecting to a VPN, as one of the requirements is a recent complete system scan.)

I tried uninstalling and reinstalling the Sophos application and have run multiple scans since then. However, the Scans window still shows “this scan has never been  completed" as seen in the screen shot below. 

Any suggestions will be much appreciated.