Local-hostname-already-in-use message regularly appearing

I have seen some earlier posts here about this problem but no one seems to have resolved it.
Often when I wake my iMac (Intel, 10.5.4) from overnight sleep there is a message greeting me "This computer's local hostname 'XX.local' is already in use on this network. The name has been changed to 'XX-2.local'." I got as far as XX-65 the other day and thought it might be time to seek a solution.
There is a router, a laptop, and a couple of Slim Devices/Logitech Squeezeboxes on the network. None has the same name as the iMac.
It's driving me bonkers. No harm done, of course, but it's a real pain to keep changing it back to the original name, and still it keeps bombarding me with these messages.
Any thoughts, oh wise ones?

It is possible that your router is also acting a local dns server and as such caching your devices host names.
A fix for this would be to assign a fixed ip address to your mac.

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Local hostname already in use - can't figure out what's going on

I've been having issues with a wireless router and I think the problem lies somewhere within my computer. As I switch back and forth from trying to connect to the internet via my router or directly connected to my cable modem, I will often get this error:
"This computer's local hostname "xyz" is already in use on this network"
There is only one compuer on the network, however and I cannot figure out what's going on.
I have 2 users set up on this machine, but I'm the admin and acting as such. Even with no other networked equipment hooked up to my Mac (except for the cable modem) this problem won't go away.
I guess my real quesiton is what causes this and where should I go to troubleshoot things?
I'm running 10.4.6, connect to my ISP using DHCP and have the same problem with both a D-Link and Linksys router.
Any ideas?
Thanks!

Thanks very much for your help, fu.
If your previous setup follows a flow like this: RCA
CableModem-->NetGear Router-->AirPortExpress, there's
something misconfigured routing-wise in your network.
You have to decide which device (Netgear or AirPort
Xpress) will handle the routing in your network.
Previous to these problems, that was the basic flow of my network. The netgear router also fed a wired connection into a Wintel PC, and the AirPort Express hosted a wireless network that was extended by a second Airport Express. And that second AE connected to a ReplayTV with a wired connection. And then, of course, the PowerBook got Internet access wirelessly through the AE-hosted network. And that was it.
That network always was configured so that the netgear router assigned IP addresses using DHCP, and the Airport Expresses would not assign IP addresses (i.e., "Distribute IP addresses" was NOT checked when you look at the configuration in Airport Admin Utility).
How big is your network j? just 1 Mac (your
PowerBook)?
That was the state of the network a couple of days ago when I posted this. I have established that the PowerBook gets access to the Internet just fine directly though the cable modem, and just fine when it is the only wired connection to the router.
Let's deal with your Mac first:
Start with your Mac connected directly to the cable
Modem. (When your mac is attached directly to the
Cable Modem, do you use DHCP?)
Go to SystemPreferences-->Sharing and type a Computer
Name other than the default one
Open Applications-->Utilities-->Terminal and type
lookupd -flushcache (press Return) and reboot
the Mac.
I did this.
One way to fix your network is to have the NetGear do
the routing, and the AirPort Express to (just) extend
your (wired) network wirelessly (No routing will be
done from the AirPortXPress, (No distribution of IP
Addresses)
I soft reset both of my Airport Expresses. I configured the first one so that it was hosting a network, but not distributing IP addresses, and the second so that it was extending that wireless network. And I plugged the host AE into the netgear router. And for a little while, that was working.
But then I got a message saying "IP Configuration 192.168.0.4 in use by 00:04:40:06:1f:82, DHCP Server 192.168.0.1". The dialog box with that message will come up periodically as long as the Airport Expresses are plugged into power and one is plugged into the router. Also, I once agaiin received the message saying the local hostname (the completely original one that I had created) was in use, and the name was being changed.
Here is the thing. I cannot figure out what has that ...0.4 IP address and ...1f:82 MAC address on the network. That is not the "Internet port MAC address" or the "LAN port MAC address" for the Netgear router. It is also not the MAC address for either of the Airport Expresses or the PowerBook's internal Ethernet card.
I accessed the router through my browser, and clicked on "Attached Devices." Here is the list of Attached Devices:
# IP Address Device Name MAC Address
1 192.168.0.2 00:11:24:08:4c:88
2 192.168.0.3 00:14:51:6d:15:7c
3 192.168.0.5 00:0a:95:da:4f:24
The first two addresses are the two AE's, and the third is the internal Ethernet card of the PowerBook.
I ran "Netstat" under the Network Utility to get "Routing Table Information," and here is what I get (with some identifying info removed):
Internet:
Destination Gateway Flags Refs Use Netif Expire
default 192.168.0.1 UGSc 23 10 en0
127 localhost UCS 0 0 lo0
localhost localhost UH 11 2400 lo0
169.254 link#4 UCS 0 0 en0
192.168.0 link#4 UCS 3 0 en0
192.168.0.4 link#4 UHLW 1 1 en0
192.168.0.5 localhost UHS 0 14 lo0
Internet6:
Destination Gateway Flags Netif Expire
localhost link#1 UHL lo0
localhost Uc lo0
localhost link#1 UHL lo0
link#4 UC en0
justin-and-***** 0:a:95:da:4f:24 UHL lo0
**************bedro 0:14:51:6d:15:7c UHLW en0
link#5 UC en1
justin-and-***** 0:a:95:f3:3e:df UHL lo0
**************bedro 0:14:51:6d:15:7c UHLW en1
ff01:: localhost U lo0
ff02::%lo0 localhost UC lo0
ff02::%en0 link#4 UC en0
ff02::%en1 link#5 UC en1
Any ideas? Thanks again for your help.

Does anyone have a fix for the "Local Hostname Already in use..."-bug?

I get this message + an incremental change in hoist name upon each wakeup (iMac, not me!) from sleep. I need a permanent fix, I would not like to play with Aiport settings etc. This issue came afetr upgrade to OSX 10.7.4. Will Mountain Lion fix it?
Mike

Tuomasveturi wrote:
I get this message + an incremental change in hoist name upon each wakeup (iMac, not me!) from sleep. I need a permanent fix, I would not like to play with Aiport settings etc. This issue came afetr upgrade to OSX 10.7.4. Will Mountain Lion fix it?
Mike
Never seen it. What makes you think it is a bug? Have seen no reports of it. Sounds like it is all within your settings.
Pete

I get this message:This computer's local hostname "x-8.local" is already in use on this network. The name has been changed to "x-9.local" I have turned off sharing and it continues to upgrade name. What is the fix?

I get this message: This computer’s local hostname “x-8.local” is already in use on this network. The name has been changed to “x-9.local” I have turned off sharing and it continues to upgrade name. What is the fix?

Hi, this is a common problem, mostly just irksome though.
It can have many cause, like using more than one Interface for connections, Router temporarily losing x.local & seeing a new connection with x.local already used, insists it must be x-1.local, x-2.local, etc..
What all Sharing do you have enabled?
Some possible fixes...
http://forums.macrumors.com/showthread.php?t=542899
https://discussions.apple.com/thread/3941367

Should I ok "this computer's local hostname Irma-Mac-mini-local" is already in use on this network. The name has been changed to Irma2 Mac-mini 2-local

Should I ok this message-this computer's local hostname Irma's Mac-mini-local is already in use on this network. The name has been changed to Irma's Mac-mini-2local

Don't think this is a conflict with IP Addresses or computer names
= DHCP hangover when computer renews DHCP lease
There is no actual other computer
It just appears that way when reconnects so creates new -2 computer name
What types of names do you use your computers ?
Whether you name them after quantum particles or the romantic poets...
They will each start to be appended with "-2" then "-3" etc if you auto configure network settings from Airport Router DHCP service and you have this Change computer name issue where pop up window states name is already being used on your LAN
As stated previous post you can reset the computer name in SysPrefs / Sharing / Edit button
And restart Router or renew all DHCP leases (if persists in not allowing original name)
Can now press Edit and reset name of choice
But for Fix see link above

Every time i wake my mac i get This computer's local hostname "D-360.local" is already in use on this network. The name has been changed to "D-444.local".

error message that my local host name is in use and the system generates a new one every time I wake my mac the error mssg reads This computer’s local hostname “D-360.local” is already in use on this network. The name has been changed to “D-444.local”.

There are several possible causes for this behavior.
1. Two (or more) computers on the local network have the same Bonjour name, such as "X's-MacBook-Pro.local". Resolve the name conflict by renaming one or more of them in the Sharing preference pane.
2. You have two simultaneous connections to the same local network: probably Ethernet and Wi-Fi. If applicable, disconnect the Ethernet cable or turn off Wi-Fi.
3. A Mac wakes from sleep due to network traffic. This is a bug in OS X that may only affect some models.
4. A device that gets its network address from the router wakes from sleep, and the address it was using before has been assigned to another device.
5. A third-party wireless router has incompatible settings or firmware. In that case, refer to the manufacturer or ISP for support. Restarting the router may help, temporarily.
6. See also this support article.

What does this mean? This computer's local hostname "Linda-Daviss-iMac-4.local" is already in use on this network. The name has been changed to "Linda-Daviss-iMac-5.local".

What does this mean: This computer’s local hostname “Linda-Daviss-iMac-4.local” is already in use on this network. The name has been changed to “Linda-Daviss-iMac-5.local”.
When I came back to my computer this message was on the screen. Should I be concerned ? or doing something?

Sometimes this message means that you have two simultaneous connections to the same local network: probably Ethernet and Wi-Fi. Disconnect the Ethernet cable or turn off Wi-Fi.
Sometimes it happens because a device that gets its network address from the router wakes from sleep, and the address it was using before has been assigned to another device.
Rename the computer in the Sharing preference pane.

IMAC.local is already in use

I keep getting this message every month or so. I change the Network back to "tg-imac.local" and in about the same amount of time, this error comes up again:
The error reads (it does not use the word ERROR anywhere):
This computer's local hostname "tg-IMAC.local" is already in use on this network. The name has been changed to "tg-IMAC-2.local".
To change the local hostname, open System Preferences and click Sharing, then click "Edit" and type the name in the local Hostname field.
The only option is OK to close the message.
I'm getting real tired of changing it back, and having this message pop up again not too long after. I do have 2 IOS devices connected via Wi-Fi and have the IMAC connected to my time capsule and then connected into my network box.
Any ideas how to get this to stop happening?
Thanks everyone!

I have the same issue, after reading other posts with the same issue I found a reply that makes sense in my case. (Pasted below). In my network I have 2 Airport Extreme routers and 1 Airport Timecapsule (all broadcastiing the same network name to extend wifi and allow better reach around our house for Apple TV's etc), I suspect that my iMac joins one of the 3 devices, and when it rejoins the duplicate name message appears.
Here is the post that tipped me to a possible cause;
Linc Davis
Re: Keep getting warning message about my Computers Hostname, any solutions please? May 19, 2013 8:09 AM (in response to Basil52)
Sometimes this message means that you have two simultaneous connections to the same local network: probably Ethernet and Wi-Fi. Disconnect the Ethernet cable or turn off Wi-Fi.
Sometimes it happens because a device that gets its network address from the router wakes from sleep, and the address it was using before has been assigned to another device.
Rename the computer in the Sharing preference pane.

Sudden message re "hostname already in use"

This morning when I opened my computer, a message was displayed saying: "This computer's local hostname "xxxx" is already in use on this network. The name has been changed to "xxxx"." I had done nothing to change the hostname. What could have caused the message to appear? Is this a sign that someone has hacked into my network somehow?

This usually means another computer on your network is using the same hostname. However, users with only one computer also report this error on occasion. It's not clear what exactly causes it to happen, but you can change it back to what you were using in the Sharing preferences pane.
You will find an interesting discussion and possibly permanent solution here: Prevent the Terminal host name from changing.

Why do I get the messagehis cowhy do I get the messageThis computer's local hostname "lenajs-imac.local" is alreamputer's local hostname "lenajs-imac.local" is already in use on this network. The name has been changed to "lenajs-imac-2.local".

why do I get the message "this computers local host name ______is already in use by the network

Usually this message means that you may have two simultaneous connections to the same local network: probably Ethernet and Wi-Fi. Disconnect the Ethernet cable or turn off Wi-Fi. If that's not the issue, shut down any virtual machines (Parallels, VMware, or VirtualBox) that are running. Rename the computer in the Sharing preference pane.

Transport takes a long time with 'file already in use' message in tp log

Hello,
We are implementing SAP ECC 6.0 on IBM iSeries, i5/OS V5R4.
I am encountering the following problem when conducting an import on TQA system from a transport request done from DEV :
The import takes a very long time without being implemented, with the following message in the tp system log :
'WARNING: /usr/sap/trans/tmp/TQA.LOB is already in use (10), I'm waiting 1 sec (20080515222358). My name: pid 621 on MASAPTQA (tqa00)
The message keeps repeating continuously, with the pid changed each time, and the waiting time (in seconds) also changed each time.
In general, the pid does not even exist.
What could be the cause of this problem ?
Thank you in advance for your cooperation.
Best regards.
Reda Khalifa

Hello Sally,
Thank you for your interest.
I've gone through SAP note 12746.
I deleted the log file /usr/sap/trans/tmp/TQA.LOB after making sure that pid 640 which appeared in the old message in the tp system log did not exist. But this resulted in the message :
'WARNING: Cannot remove /usr/sap/trans/tmp/TQA.LOB : No such file or directory' to appear once in the tp system log and for a very long time.
I re-generated the transport profile file, and released a new transport from DEV to TQA, and tried to import this new request, and now the message in the tp system log is :
WARNING: /usr/sap/trans/tmp/DEVKK917158.TQA is already in use (20), I'm waiting 4 sec (20080516225456). My name: pid 663 on MASAPTQA', where DEVKK917158 is the transport request number generated from the DEV system.
pid 663 now corresponds to an active job (I used command WRKPID)
Any clues ?
Thank you for your cooperation.
Best regards.
Reda Khalifa

Hostname Already in Use Changes?

Frequentlly, we get "this computer's local host name on the network is changed to 1234567654-1 because it determines that the original host name "is already in use." This doesn't make network peripherals and communication between our two computers very easy. When we get the notice, we change the name (number) back to the original and it seems fine for awhile and then returns...
I can find no apparent cause?
Thanks!

Frequentlly, we get "this computer's local host name on the network is changed to 1234567654-1 because it determines that the original host name "is already in use." This doesn't make network peripherals and communication between our two computers very easy. When we get the notice, we change the name (number) back to the original and it seems fine for awhile and then returns...
I can find no apparent cause?
Thanks!

How to fix "Microsoft Office is already in use" message?

I know I fixed this some time ago, but I just got a new computer and I forgot how to fix this problem.
I have Office on two computers on my home network. If my wife is using Entourage on one computer, and I try to bring up Word on the other computer, I get the message "Microsoft Office X can not start because Microsoft Office is already in use". The original fix was to use the firewall and block a certain port, but I can't remember now. The problem is with the new computer. If I reverse it and bring up an Office app on my old computer, I can bring it up on the new computer. So it must be a firewall setting on the new Mac that is missing.
Can anyone please help?
Thanks,
Alfredo

I asked this here before and got an answer. I don't see anything wrong if you have a small network at home, as long as you aren't using it at the same time. My big complaint is that I can't run one app (Entourage) and another app (Word) at the same time on two different computers.
Alfredo

Why would this appear on my screen? This computer's local hostname "Lloyds-iMac-4.local" is already in use on this network. The name has been changed to "Lloyds-iMac-5.local".

This popped up on my screen. No idea why. Have i been hacked?

There are several possible causes for this behavior.
1. Two (or more) computers on the local network have the same Bonjour name, such as "X's-MacBook-Pro.local". Resolve the name conflict by renaming one or more of them in the Sharing preference pane.
2. You have two simultaneous connections to the same local network: probably Ethernet and Wi-Fi. If applicable, disconnect the Ethernet cable or turn off Wi-Fi.
3. A Mac wakes from sleep due to network traffic. This is a bug in OS X that may only affect some models.
4. A device that gets its network address from the router wakes from sleep, and the address it was using before has been assigned to another device.
5. A third-party wireless router has incompatible settings or firmware. In that case, refer to the manufacturer or ISP for support. Restarting the router may help, temporarily.
6. See also this support article.

Certificate deployment - Certificate already in use message

I am deploying a site with one Primary and one remote DP, all communication must by HTTPS. Each of the two has MP and DP roles installed, however only the primary has both enrollment roles installed. Should the remote DP has enrollment roles as
well? Is it needed?
When trying to add to the remote DP the same certificate I added to the primary without any issues, I get the following:
Not sure if this is an error or not, my thought was the same cert should be used for all DP in the same site?
Thanks

Not sure what you mean by enrollment roles, are you talking about the device enrollment role?
The cert you are specifying above is essentially a temporary cert that is used by PXE booted clients during the OSD process so it will be used many times over by different clients thus using it on both PXE enabled DPs isn't a big deal to my knowledge.
As an additional note, placing an MP at a remote location is not recommended because clients do not use MPs based on their location, thus clients can and will use any/all MPs within a primary site and there is no specific way to control this. Multiple
MPs within a primary are for high availability (and cross forest scenarios), not remote locations.
Jason | http://blog.configmgrftw.com

Local-hostname-already-in-use message regularly appearing

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