Exactly. I had a scene I started in 4.5 and it rendered fine untill I copied it a bunch of times to try to get it to error. I had like 15 the errors started and at 21 copies and then It finally went. What was you RAM usage when you got those errors? I noticed it would get up to like 1.5 and it would go. Batch render worked though without the errors and the RAM climbed to like 1.7 gig.