This is a variation on a previous post about the problem but more specific as I tried various things I have 2 W7/64 ultimate machines, one desktop, one laptop. Both connected by cable to the same switch, which is then connected to another switch which has a NAS box attached. The desktop can map network drives on a NAS box using name, not IP address and seems to map them using SMB. The laptop will map it only with IP address, not name, but it does this by starting the WebClient service and uses WebDAV. However, this does not work properly - examples of the problems seen are It does not see some directories on the share, for example, if from a command prompt, I type cd mu<tab> then it pauses and completes 'Music'. If I then type 'cd mp3' it responds with 'The system cannot find the path specified' - it DOES exist. It also shows the drive in Explorer as '29.8 GB free of 63.9 GB', whereasthe desktop shows 861GB free of 1.34TB It is horrendously slow, e.g. if I go to the drive, it takes several seconds to give a directory listing. So, I've been trying to work out why the laptop will force WebDAV by starting the WebClient service with the aim to force it to use CIFS. I've tried the following Safe mode with networking - all is fine Clean boot with only Microsoft services enabled - uses WebDAV Disable WebClient service - map network drive fails with network error 0x800704b3 I tried adding the NAS name to the laptop hosts file (desktop does not have NAS name in hosts file) - no difference Set the network adapter WINS to force use of NetBIOS over TCP/IP - no difference Installed latest updates - no difference Used msconfig to disable all services - pretty much nothing works after that! Tried both cable and wireless networks on the laptop - no difference Compared the Services in both machines - nothing stands out as obviously different. They both have SSDP, Workstation, Server, Computer Browser Run Wireshark to see what's going on - clearly laptop is using WebDAV - uses HTTP to access share on port 80 - desktop uses port 445 Joined a homegroup on the laptop as it was not previously joined compared with desktop - no difference Checked advanced sharing for home/work - all options same between laptop/desktop Stopped Windows Firewall service - no difference Disabled IPv6 in adapter properties - no difference Compared HKLM\SYSTEM\CurrentControlSet\services\LanmanServer|Workstation\Linkage and noticed that \Device\NetbiosSmb was after other devices in the Bind/Export/Route keys, so moved it up to first entry - no difference Odd thing is that this was working 6 weeks ago before I went overseas, but no longer works on my return. During my time away I installed MS Live Meeting and MS Linc Attendee, both of which I have uninstalled to no effect. Wireshark shows from the desktop machine that it resolves the name with NetBIOS name service and uses SMB protocol to talk to the NAS. Laptop uses WebDAV showing HTTP OPTIONS and PROPFIND requests. Unfortunately all my restore points have gone because I disabled all services in msconfig, so I can't restore a previous snapshot to test that theory :( I'd really appreciate some help with this otherwise seems like I'll have to reinstall W7, which takes about 2 days to get all stuff reinstalled!

I installed Service Pack 1 and that seems to have fixed the problem.