I recently installed Windows 10 on a computer containing 3 internal and 8 external hard drives. Although all the drives show up in Disk Management and File Explorer, one of the internal drives isn't listed under "Indexing Options" so I can't get the files indexed. Since I can't get them indexed, I can't add them to a Library. I can access the drive, I can share the folders with my homegroup. I can view the files from the computers in my homegroup. I just can't add the relevant folder to the library! Can anybody explain this weirdness?