In order to troubleshoot this issue please follow the steps from the detailed guide below:
1. Repair Bitdefender 2016 from Control Panel.
a. Press Windows key + R from the keyboard.
b. Type appwiz.cpl in the command box that appears and press Enter.
c. This will bring up Programs and features in Control Panel. Locate the Bitdefender product in the list, right click on it and choose Uninstall.
d. You will be prompted if you wish to Uninstall or Repair the product. Please choose Repair.
e. Wait for the process to complete and then restart your computer for the changes to take effect.
2. Run a Windows check disk. In order to do that, please follow the steps from this link:
For Windows 8, 8.1 and 10:
a. Open the This PC window (Windows + E)
b. Right click the drive that you want to check for errors, and click on Properties.
c. Click on theTools tab, and click on the Check button under Error Checking.
For Windows 7:
Follow the steps from this Microsoft article: https://support.microsoft.com/en-us/kb/2641432
3. Please also run the DISM command by following these steps:
a. Open an elevated command prompt. To do this, press Start and type Command Prompt
b. Right-click on Command Prompt and then click Run as administrator.
c. Click Yes on the User Account Control Prompt.
d. Type the following command, and then press Enter:
DISM.exe /Online /Cleanup-image /Restorehealth
4. Run the System File Checker by following the guide bellow: