In the past three days I have had two Dell Dim 9200 Vista workstations say they had IP conflicts, the first system I was able to assign a new IP address even though the original was not being used anywhere else and it seemed to fix the problem, now I have a second Dell Dim 9200 same as the first system giving me the same error about an IP conflict, so I do the same thing and change the IP address but this time no matter what number I change it to it still says I have an IP conflict? I tried 8 IPs and they all say that they are being used. I uninstalled the NIC in device manager then rebooted and same problem so no matter what IP on my network I use, it tells me it has a conflict, has anyone else seen this problem and know how to fix it? I a computer that I cannot use right now and a user who is going to be upset come Monday when they still cannot use their brand new computer. Thanks.

It gets weirder now, I decided to try and change the network so I went from X.X.154.69 to X.X.155.69 and now it works fine, so why would it think that any IP address on the 154 network is a duplicate? Our IP addresses are tracked through a on-line database that makes you put in the Mac address and if your system is not in the database you cannot get on the network even if you guess at an IP address, so I know what IP addresses are used and what are not so I still have no idea of why this happened maybe a new bug in Vista, hope someone reads this that can shed a little light and maybe figure out what the problem is before it effects more people. Matt

I am having a similar problem - vista laptop and xp desktop are linked on my home network, Everything has been running properly. However, I have been taking my laptop out for the past month - 2 weeks ago when I brought it back, I started getting windows error message - detected and ip address conflict. Nothing has changed on my computer except maybe some windows behind the scenes updates - and a simply accounting upgrade. I have a program called network magic and it shows the computers have different ip addresses. Therefore there seems to be no conflict. I have turned the router off, given the vista a static ip that is different - I am thinking it is a vista problem. The error message comes up every couple of minutes and is making me crazy. The Xp desktop says nothing about a conflict. Both machines have access to the internet at the same time and different times. Any thoughts would be appreciated.

I've seen this problem as well and this hotfix solved the problem http://support.microsoft.com/kb/929451/en-us