Another device on the network is using your computers IP Address. If you continue to have problems, change the IP Address of this computer!?

What that means is you were forcing your Mac Pro to always use the network address 192.168.1.67 since yo had manually assigned that. Normally this would be fine, your router would check for active addresses in use and assign a different address to any computers trying to join the network. The problem could arrise if your Mac Pro is off-line and the router had already assigned 192.168.1.67 to one of your other computers. When you tried to log in with your Mac Pro you would get the addressing conflict that you noticed.

Setting all computers to using DHCP will let the router handle the addressing.

I would check all of your computers and PC's. 67 is far enough in the middle of the range that I am surprised if the DHCP had handed that out to any client computer. You may have more than one of your computers set to manually assigned address using that same address. Make sure you set all of them to DHCP only. Also, check if you have any other IP devices like a printer or NAS drive that is using static addressing. Those can cause the same issues. I prefer to use static addressing with those as it makes it easier to find them on the network and since they are pretty much always left on the router knows they are there.

On each Mac, select  ▹ System Preferences ▹ Network ▹ Advanced ▹ TCP/IP. What values are shown for the following:

Configure IPv4

IPv4 Address

Subnet Mask

Router

For those of you with wonky wireless issues try the following settings:

1. Network / TCP/IP - Configure IPv6: set to 'Automatically'

2. Network / TCP/IP - Click on 'Renew DHCP Lease'.

3. Confirgure IPv4: set to 'Using DHCP'

In my house network we have 2 x MacBook Pros, 2 x iMacs, 2 x iPhones (4s and a 5),

1 x iPad2 and 1 Epson Wireless Printer.

We are running an old school Linksys Router '82.111G'.

I haven't had any ip issues - until we updated the

iPhones and iPads to IOS7. Then the 'using the

same IP address' warning popped up on our iMacs

a few times. I fixed it by using #2 above.

Papanate

Configure IPv4 - Using DHCP with manual address

Change that to "Using DHCP." Apply the change and close the window.

THANK YOU! I was just sure I was hacked. I tried to open a link to "EverNote" sent in a text message from an old colleague. My phone slowed down then froze (I have an iphone5). I tried to turn off the phone, but it wouldn't turn off. I went to my laptop to search for an answer and the window popped right up saying that another device was using my ip address. I ran over and pulled the plug on the router, then removed the batteries from both my iPhone and my MacBook.

I later took them to my office and booted up my MacBook. Everything seemed fine. I proceeded to change all my passwords (still changing some less important ones as I go along). I finally put the battery back in my phone, but took it off wi-fi while I was home. Meanwhile, my husband changed the user id and password on our wi-fi. Everything seems to be working fine.

We had 2 wi-fi addresses from the one router (don't know why), and a few days later, I realized that my computer was defaulting to the 2nd address, when I got the message again about another device on my ip address. I had my phone and computer forget the second one. It's been very stressful. I am so glad to know that it was probably from my recent iPhone update to OS7.

Had the same problem, bought ipscanner home and found that NO devices had the IP address in the message.

Linc, I have the same issue. This happened about a year ago and was thought to be a modem/router issue. I switched to Airport and all had been fine until about a week ago. Adding a note as my settings are slightly different from tsatterca1's above. Setting are:

Configure IPv4: Using DHCP

IPv4 Address: 192.168.1.84

Subnet Mask: 255.255.255.0

Router: 192.168.1.254

Configure IPv6: Off

Any help would be appreciated.

Hi! I had the same issue. One day when I got home i had the same warning. After that everything is messed up. Please help me. Im no techy. I barely understand the conversation. But I really need help to resolve this. I have tried resetting the password of my router but nothing has changed. Both our phones arent able to connect to wifi, they recognised it but wont connect. Also, apologies for my ignorance but could my computer be hacked because of it? I suddenly need to log-in to facebook and other apps that I didnt eve log-out. Im really scared now. I dont know what to do. Please help me Sir.

I've just recently begun having the same problem, but under different circumstances. I thought I would describe my problem before I manually change the IP address, in case it is a larger problem:

About three weeks ago, I installed a SSD into my 2011 MacMini. I followed directions online to run the SSD and original HD as a Fusion Drive (I'm not completely convinced this setup is working exactly like an Apple-installed Fusion Drive, but it does show as a single drive, is noticably faster, and I haven't had any issues, so I am content with it for now). About a week later, I got the message about another device on the network using my computer's IP Address on the login screen after waking. When I logged in, I noticed it was not connected to the wi-fi, but I was able to connect by selecting my network. When I got the message again, I did some digging and found that the name for the mini on my network changed sporadically from MACMINI-587E6A to the 12-digit MAC Adress. I will occasionally be kicked off the wi-fi, but it connects again quickly. Both named devices use the same IP address, obviously. I've tried turning everything off and back on, but I'm still having the same issues. The mini is set to use DHCP, and I am not having issues with any other devices (Apple TV, iPad, Wii)

I guess my concern is that I've mixed something up somewhere, and the old and new configurations are both trying to connect and causing conflicts. Could it make it worse by changing one (or both) of the IP addreses? Does anyone know why it might be seen as two seperate devices?

Any advice or opinions would be much appreciated!

Thanks,

David

Hello Linc ,

I live in a dorm for University and my macbook air (med 2013 ) is connected to it like other students in dorm ...and the macbook Air shows a message that another device is using my computer IP address . I don't have another device how to fix this and can people( in the dorm ) see my contents of computer ? such as pictures ,files and videos ?

my settings show

configure ipv4 : using DHCP

thank you so much i would appreciate your help .

sincerely ,

Ameer

I have this error message problem. I've tried all the fixes mentioned above but it persists. My settings are:

Configure IPv4: Using DHCP

Configure IPv6: Automatically

Clicking "Renew DHCP Lease" hasn't helped.

Are the IP addresses listed in the this discussion are local/privite, not routable addresses. The same address are used by millions if users.

https://en.wikipedia.org/wiki/Private_network

What you do not what to post is your public IP address, that is the address assigned by your service provider