For players using bitdefender, you refer to the following steps contributed by SuQee:
The solution to this problem is simple = YOU NEED TO EXLCUDE THE GAME FROM ACTIVE VIRUS CONTROL
- Open your BD Antivirus (mine is Bit Defender Total Security 2011)
- Switch to Expert View by using the Options menu in the upper right corner.
- Open the Antivirus section, and in Shield tab click the Advanced Settings button. Check that Active Virus Controlis enabled.
- Access the Exclusions tab.
- Search for the application and point to its executable file/ [How? Click the '+' sign, then find your DNLauncher.exe and DragonNest.exe]
- Notice that a rule will appear in the table with the default action Allowed.
- From the drop down list you can decide to allow or block it. [in this case, we are soooo gonna allow it]
- To complete the task, click OK