I have two computers in a home network, one, "W7", running Windows 7 and one, "XP", running Windows XP. They have the same Workgroup, say "WG". XP shares a printer and a couple of folders to everyone. Yesterday I managed to add a network drive in W7 specifying "\\XP\Share" and "Z:", and copied a file from \\XP\Share\File.ext to the desktop on W7. Later the same day the network drive was no longer accessible. I cannot remember the exact error message, sorry. In order to debug the problem, I ran Wireshark on W7 to see the exchanges on the network. I right-clicked the Desktop, selected New and Shortcut. In the target field I wrote \\XP\Share and I clicked Next. After some seconds I got a popup dialog saying (translating from Norwegian, the standard English dialog may differ): Cannot find the file \\XP\Share. However, in Wireshark, I could see W7 was emitting "Name Query NB XP<20>" 18 times, approximately once per second, and every time it got a response "Name Query Response NB 192.168.0.117" from XP. The queries are broadcast to 192.168.0.255, responses are sent to 192.168.0.134, the correct IP address of W7. The responses are reaching W7 since I am seeing them in Wireshark which is running on W7. How come W7 does not "find" XP? I find it unlikely that this could be related to any share permission issues, first because it worked earlier the same day, and second because I suppose W7 would not keep repeating the query over neary 20 seconds if it recognized the responses. Share permission issues cannot enter the picture before W7 actually asks XP for the share.

Hi, Please kindly refer to the following steps to check it accordingly. 1. Temporarily disable firewall and test. 2. Is the 192.168.0.117 from Windows XP? 3. Try to use IP address to access the XP . 4. Check the permission of the Shared folder. 5. Please advise me the error message. 6. If the red X appears on Z drive? 7. I Suggest you to enable NTLMv2 in Windows XP to have a try.

1. Windows firewall was/is off. However, I found I have F-Secure Internet Security 2011 with firewall enabled. I have now temporarily disabled this firewall. Thanks for suggesting this. 2. Yes, 192.168.0.117 is the XP, and 192.168.0.134 is the W7. 3. I tried to create a shortcut to \\192.168.0.117\Share (before disabling the F-secure firewall), and it worked! I could double click the shortcut and an explorer window opened with all the expected file names in it. Thanks for suggesting this one. 4. Permissions: On the XP, opening the parent folder in an explorer window, right-clicking the shared folder (which is shown with a hand holding it) and selecting Properties, the Properties dialog opens. There is no Security tab. There is a Sharing tab, and the options "Share with network users" and "Allow network users to change my files" are both selected. (I am translating the names of these options from Norwegian. The actual English names of these options may be different.) 5. I will defer this one. It will take some work to recreate the situation and get the same error message. 6. Yes, there was a red X across the shortcut and (If my memory serves me) across the Z: drive in Computer. 7. I don't know how to enable NTLMv2 on the XP, and I will defer it since we have found the F-Secure firewall appears to cause the failure. I will look around for a way to tell F-Secure about this. I also wonder why the firewall only blocked the name lookup responses after I had been using the share a couple of times. Thanks again.