Unity running out of memory

Hello, I recently made a big main level scene with lots of detail rocks, trees, buildings etc. Whenever I try to run the game i get a long vertical popup telling me i dont have enough allocated memory or something along those lines. I was wondering if there is anyway to fix this without deleting some models from the scene. Ive got 5gig left on my hardrive, the project being about 2 gig. I am currently running Windows on a partition on my IMac I’m sure its not a ram issue seeing as i have 8 gig. I dont really want to post the error but I will if it is neccessary, It takes time to recreate as the scene gets deleted everytime haha. Thanks in advance for any advice you can give me to this problem. Just ask if you want me to post the error :).

Here is the error the black spot is my skype :smiley:

[1562-unity+error.png|1562]

You did go out of ram.
Must be one massive scene.
Try to backtrack from where you last managed to run the scene.
What exactly went wrong is anyones guess from the information given.