Updates Don't Seem To Be Installing

[nekton]

I have FortiClient 5.2.3.0633 installed. 

Over the last few months I have been getting the following message:

FortiClient recently updated itself.

  You must reboot your PC to allow FortiClient to finish the update.   Please reboot by clicking the Reboot button. If you don't want to reboot now, click the Do Not Reboot button.   When I reboot, I get the same message again as if nothing has happened. I am not quite sure where to start to debug why I am getting this message.