The issue you are experiencing is due to having a 32 bit OS. Please refer to this link and scroll down to the part about 32 bit OS.
"For 32-Bit Machines
There are reports of reporting crashing when transitioning on 32-bit machines. We are aware of the issue and attempting to fix it. This issue did come up on Wasteland 2, which is another Unity project, and a workaround was discovered by their fans: here
You can change your system settings on your computer to increase RAM used by a single application. However, there are inherent risks involved when changing settings involving your operating system and any attempts to change your system settings will be at your own risk. Obsidian is not liable for any issues that might occur with those settings."