Have you tried restarting solidworks? if that doesn't work, try restarting your PC.
Actually, that was the first two things I tried because, honestly, I didn't know what else to try.
I first noticed the problem yesterday and even after being shut down over night, the Render command still failed to work today.
I even went as far as to think "possible corrupted individual file" so I open another random file, tried to Render it and still no luck????