B3 wont start. crashes before loading main menu

just moved from R7 to B3. New folder, freshly updated EFT, no mods.

dropped R3 files into folder as instructed and EFT keeps crashing before loading into the main menu.

My R7 still works fine, same for live EFT, it's just B3 that crashes.

Just closes down and brings back the launcher.
It gets to Profile Data Loading, "buffering" circle freezes and game closes.

Would it matter that it never started properly and that would be the moment to choose name, Bear/Usec etc?



edit:
downloaded B4, new folder, fresh SPT install, problem persists

update:
looks like it was a problem with my hard drive - after moving folder to a different physical drive everything works fine.
sorry for time wasting