Moving your terrain builder project files to a new path / directory from lets say c:\arma3tools\ into d:\arma3tools\ or just d:\arma3tools\ d:\mynewtools\ dir will almost every time break the project that when you export terrain WRP file the WRP does not get saved properly.
You notice it breaking during exporting then terrain builder will not show you the object export count.
It doesn't happen every time and I have been unable to pinpoint why, but projects will break 95% times when you move them. For example one time I moved around 50 projects and "a few" did not break.