Prepass buckets are not computing - buckets named unknown

[stevesideas]

I have been waiting for a 5000x3500 size image to pre-pass. I had a network problem with 2 of the systems during the pre-pass and now im left with 3 buckets that are not being computed by any of my render machines. They are all named unknown in the bucket/network name.

Shall I stop the render, save the pre-pass and just add to prepass the area that didnt calculate the first time round ??

[vaslavo]

did someone found a solution for this?, it still happends with some big resolution images.