This machine has two physical HDDs. One of those drives has three partitions. On those three partitions are three separate OS's: Windows Vista, 7, and 10. The second HD has four partitions. I would like to have three identical email programs, one in each OS, and have them all store and share their emails and addresses, in the same store folder, on one of the partitions on the second HDD. Does anyone know of an email client that can accommodate that setup.