Can you render out to bmp rather than an animation file type?  That way, you can render smaller sections.  Say render frames 1-25, 26-50, etc.  Then, using a free program like Vurtualdub, make it into a movie format. 

This is the safest way to render an animation, but does take some post work to “assemble” the frames into a movie format.**  **Since animations can take days to render, by rendering to bmp or jpg each frame is saved when done rendering. Going with a movie format like *.avi or *.mov - if anything happens while rendering, you loose it all!

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