In the main FancyCache for VOLUME screen, I suggest not displaying volumes that do not have drive letters associated with them. It makes no sense to cache a volume that has no drive letter, since Windows does not see the volume or use it.
it was designed for a scenario such as below: A volume was associated with a dirve letter and with FC enabled. Later user removed the drive letter but he/she forgot to disable FC. If FC doesn't show such volumes, then there's no easy way to disable FC on them unless they are associated with drive letters again.
Let me also pose this to the group: those who use TrueCrypt, will know that there are (encrypted) volumes without drive letters, until they are mounted. So maybe someone can speak to that scenario as well. (I run TC, but with FC DISK).
Many Fibre Channel SAN software drivers use non-drive letter disks and re-mount them as network shares at the same time (e.g. Tivoli SANergy and others). Its a common method. It should be fully up to the user to decide wether a drive should be cached or not. Don't rule out options due to not knowing better