I have completed an application I have made in Visual Studio 14.0, but when I tried to publish the program, I get an error as Visual Studio cannot find \'SignTool.exe\'. I
No Worries! I have found the solution! I just installed https://msdn.microsoft.com/en-us/windows/desktop/bg162891.aspx and it all worked fine :)
I had the same issue but installing the Windows 8.1 SDK as per Catquatwa's answer did not work for me (signtool.exe was still missing from C:\Program Files (x86)\Microsoft SDKs\Windows\vX\Bin).
I stumbled across this solution: http://www.benedykt.net/2015/08/12/missing-signtool-exe-w-visual-studio-2015/
Basically, for VS 2015, this would be: