I installed W8 Pro on a hdd with 13 partitions. When I attached another hdd with 12 partitions, W8 would not boot. In fact I cannot even do a fresh install of W8 with both hdds attached. I tried hiding most of the partitions on the second hdd, no luck. So let me know if : - you are running W8 with more than say 24 partitions, or - you faced a similar problem ( so I'll know I have not messed up ) Thanks.