Question : Problem: Cannot back up second partition

I purchased the Premium verison of Carbonite. I have two partitions on the same drive C: - C: and Z: Cabonite is backing up selected folders on the C: drive but it will not allow me to back up any folders on the Z: drive. This is very strange because it does allow me to back up folders on a second drive on my computer. I have asked Carbonite repeatedly for a solution but they simply ignore my question. The Z: drive is set for sharing and to allow network users to change the content. I have no idea where to go from here.

Answer : Problem: Cannot back up second partition

no, it can only back up physical disk, you said that the z: is a shared folder...it's not a disk. Best way to back that up would be to copy the files and compress them and then put them on your back up media.