I've run through the installation process for the new available version of SMAPI and configured it through STEAM, however whenever I try to run it it gives me a missing executable error. *It might be important to note that the StardewModdingAPI.exe did not appear in my game folder once I installed it.
It sounds like your antivirus is deleting the SMAPI files; see SMAPI files disappear or your antivirus complains in the troubleshooting guide for more info.