We have a problem with our Windows XP laptops on our corporate network. Users will be online and happily working away when suddenly Windows XP will go to the "offline" state. If they click on the offline icon and choose OK, it will successfully reconnect immediately and continue working. I was wondering if this is because of the media sensing or some other feature, as the networking icon does not display a disconnected icon.
Now Microsoft has a fix for this problem disguised as a security hotfix. The solution is, therefore, to apply the hotfix described in Flaw in SMB signing may permit group policy to be modified and all should be much better. If that doesn't work, set the REG_DWORD value enablesecuritysignature in HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\lanmanserver\parameters to 0.
This was first published in March 2003