@elysebluemoon I am having the exact same issue, my game was working fine in singleplayer 1.4.2, but ever since I updated to the latest patch today 1.5.1 I believe, my game does not launch, I can provide video evidence if you need clarification.
Installed community-made modifications: Deleted all mods
Computer Specs:
OS: Windows 10
GPU: Geforce GTX 1060 6gb SSC
CPU: Ryzen 5 1600
RAM: 16gb 2666mhz
Motherboard: MSI b350 Tomahawk
Storage Device (HDD/SSD): SSD game is stored on my D: drive