Once the issue has been clarified, it is recommended to disable any antivirus you have installed before proceeding with the installation.
Download both Setup and Client installation files
Proceed to install the Setup. The default installation folder is "C:\KiotoStory\"
After installing it if you have the antivirus activated (Windows Defender) it will surely eliminate the game launcher (Client)
Add the folder where you installed the Setup to the exceptions of your antivirus. This could vary depending on the antivirus you are using.
If you are only using Windows Defender you can use this link as a reference: Video Tutorial
(Remember to add the Setup folder you just installed, which in default would be "C: \ KiotoStory \")
Now you can install the Client in the folder where you installed the Setup "C:\KiotoStory\" (Run the Client's installer and make sure to indicate the address where you installed the Setup)
If nothing happens when you run the game or you get an error remember:
1- Our Client requires .NET Framework 4.6.1 and Visual C++ redist
2- In the properties of the executable or shortcut to run the game select: Run with Windows 98/XP/7 compatibility