I've found that sharing files / folders from W7 x64 with XP based machines on my network is fraught with difficulties; yesterday I spent 2-3 hours unsuccessfully trying to share some folders on my W7 x64 machine with an XP Pro SP2 system on my network.However, this is not the primary reason for this post, while changing general network settings and individual sharing settings for folders on the W7 system, I suddenly LOST PERMISSIONS / OWNERSHIP OF THE SYSTEM DRIVE ROOT! (c:\)Not only was my admin level account locked out of the drive, but any new admin accounts created also were and when I managed to activate the built in Administrator account, this was also locked out of the drive!After another 2-3 hours of trying to regain ownership of the C drive and being met with "no permissions" at all turns (command prompt / gpedit.msc / system restore etc.), I eventually found that by right clicking the drive and selecting Properties > Security > Owner> [Edit] it was possible to takeownership of the drive where this had failed by all other routes.Anyone else encountering this issue should try the above method, however,surely this as a major / critical defect of the kind which shouldn't really be present in an RC (and from what I've researched thisor a verysimilarbug may also be present in Vista), and which should certainly be fixed before going live?Note: while I cannot report this defect definitively or steps to reproduce it, itappeared to occur when I gave up on trying to fix the network sharing permissions anddecided to copy the content I wanted to share into the Public folder;I initially mistakenly dropped shortcuts to the 2folders in question(which reside on a different HDD) intoPublic and it was when I tried to delete these shortcuts that access was first denied, from that point on I had no ownership of C:\ and only limited access to my user account folder. Steve MARTIN Tester Analyst Sopra group.