I have 5 iMacs, 1 MacBook Pro and 1 Windows computers in our home. 3 iMacs and MacBook Pro now have Lion. Other two iMacs have Snow Leopard. I am fixing a couple of Windows computers for friends (so currently have XP and Windows 7 in the house). NONE of the Windows PCs can see the Lion shares. The Snow Leopard shares show up immediately in the "My Network Places". I can see Lion PCs only if I put in \\"computer name of Lion iMac" or the IP address. However, it then prompts for user name and password and no matter what I put in (guest, my username and password, my username and password, using the domain\user name then password, etc.), I get a "...is not accessible. You might not have permission to sue this network resource. Contact the administrator of this server to find out if you have access permissions. A remote procedure call (RPC) protocol error occurred." I also have a HP Color LaserJet with the ability to "scan to a folder" which worked fine under Snow Leopard, and now it can't see the share with Lion. NOTHING has changed in my network other than the upgrades from Snow Leopard to Lion. I called Apple using my AppleCare Protection and they referred me to HP and Microsoft. I said it's not an HP or Microsoft issue as NOTHING has changed on those PCs and my Snow Leopard macs still work fine. I then got "disconnected" (or hung up on). Would love to know the answer to this if anyone has any ideas.