Thanks for all the help folks, if absolutely nothing else, it makes me feel like I'm not alone in having issues, which kinda calms me down a little, but I do think you make some valid points. The permissions idea sounds highly plausible, even probable, as it's an old company machine with different user accounts still on it; I'm not sure which one is the 'admin' one but I'll find out. As it stands, it's still rendering the same scene... as I said, this machine sucks, lol!

I'm running Win 10 Pro 32GB RAM Intel Core i7-4790K CPU @ 4.00GHz Nvidia GeForce GTX 1660 Ti

My DA Gallery: glen85.deviantart.com/gallery

Peace, love and polygons!