I have Windows 7 PRO x64, I am using a AMD Phenom II 3.4ghz quad core processor and MSI 790FX-70GD motherboard, and a Coolermaster 1200W power supply. I have 11 1.5T hard drives and 2-2.0T hard drives, (5 are connected by usb and the others by sata) . I keep losing 4 of the hard drives. They will be listed on my computer then disappear and I can't access the files. The Motherboard has 8 esata ports. I have 2 cd-rom and 1 blue ray player/burner connected to three of the sata slots; 2 are empty. I have added a esata port multiplier and a 5 port hub. I can not find out why I keep losing 4 of my hard drives. Can anyone offer suggestions as to what might cause this problem. This is my HTPC and all drives are used for music and video/dvd files. Thank you.

Try disconnecting and reconnecting the multiplier. Inspect driver for multiplier as well.

Thank you. I had tried this with no luck. I also decided to reinstall the drivers for the multiplier and now my hard drives are showing up again. I am not sure what happened as I had installed the drivers the day before I wrote this. All seems well now. Thank you for your help.

You had luck. You reinstalled the drivers as I had mentioned.

Yes, I had a lot of luck. Now if I can get my hard drive with all my music to work again I will be happy. I hope I am not loosing that drive before I can transfer my music. It's a 1.5T seagate hard drive, I will be working with that one next. Thank you again for your help. It's great that a person can come to a forum like this and get ideas and help from other people when a problem occurs. Thank you.

Thanks dude.