Sometimes the customer service of Bitdefender just suggests me to "Repair" Bitdefender to solve some issues. Although it is too simple, it can actually solve some problem.
To do this, you only need to choose the option "Repair" in the uninstall panel of Bitdefender. Following is the full procedure ever mentioned in the letter from the customer service:
1. Press at the same time the keys "Windows logo" (located between Ctrl and Alt keys) and "R".
This will bring up the Run box.
2. Type directly in the box "appwiz.cpl" and hit Enter.
3. Wait while the list is being populated, then search for 'Bitdefender Total Security 2016', right click on it and choose Uninstall.
4. A wizard will appear. Choose "Repair".
Wait for the process to complete and then restart your computer for the changes to take effect.
Please note that I received this letter when I was still using v2015. The digit in red was "5" in the original email. I think the approach for v2016 will not be much different.