Memory Crash / Hang on build Unity 4.5.3f3

I’m getting 100% Crash to desktop when trying to build my project, specifically when it’s trying to build the main game screen. Here’s the message :

90054-unnamed.png

I’m stuck on Unity 4 as the game is build around Unity 4 physics, and all attempts to port it have failed with no more time left in the budget to take this route.

Can anyone shed a light on what is causing the crash so I can fix it?

Additionally, I have the editor log files but am unable to post them here as they are above the 500kb limit. If you’d like access, I can email them over.

Many thanks.

Don’t use 4.5 we already got 5.5 and 5.6 is almost out.