I've followed all the steps from https://forum.rainmeter.net/viewtopic.php?f=103&t=27981 and totally uninstalled Rainmeter and deleted all the folders. I've then updated my video driver to the latest and installed both 4.3 Beta Release - 3279 & 4.2 Final Release - r3111 of Rainmeter, both crash on opening with no skins apart from the default.
System Info