Hi. On my File server i have two raid: 1 for system and 10 for data. I recently noticed that came fake volume Y, and i am not udersantand from where it comes??? And for any folder into this volume I can't set share access.

Looks like a mount point your Disk 1 (E: volume). Get this free utility... http://www.nirsoft.net/utils/drive_letter_view.html ...to view all of the mount points. See wherer both E: and Y: point to. P.S. There's a console exe with Windows DDK but it's way too complex to use...StarWind iSCSI SAN & NAS

it is like mapped VHD file from Backup or VSS snapshot? but, when VHD is mapped - in Disk Manager i can see it. Now i can't see.

Yes, it's a mounted VSS snapshot. See these links... http://blogs.msdn.com/b/adioltean/archive/2006/09/18/761515.aspx http://blog.uvm.edu/jgm/2007/09/13/exposing-vss-shapshots-as-a-drive-letter/ ...on how to mount / unmount VSS snapshots. Hope this helped :)StarWind iSCSI SAN & NAS