White render screen

[JCA131]

A few times this week while rendering an image larger than the render window, the top left corner of the image has turned white and not come back. When i scroll down or to the right, the image is still rendering, but the top left corner disappears. I had a rendering going for 11 hours and the entire image was fine, but after minimizing and coming back, the corner (in the size of the rendering viewport) was missing. When I try to refresh the image, it does not come back, and when I try to save, it tells me there is no image to save. Any idea why this is happening???

[Fletch]

what is your RAM usage level when this occurs?
This was just posted, hope it can help.

[JCA131]

Thanks for the response Fletch. I didn't check the RAM usage when it happened, I will pay attention to it if this happens again. And thanks for the link, sounds like a lot of those tips will help if I run into this issue again.