This computer's local hostname is already in use on this network

has anyone else experienced this issue?
The iMac will display the following error message on the screen every day or so (with the host number incresing by 1 digit each time):
This computer's local hostname "MacName.local" is already in use on this network.The name has been changed to "MacName-1.local". This continues even after I've reset the name in the System Preferences panel/sharing settings, for example ("MacName-2.local, MacName-3.local, MacName-4.local" etc).
Please advise
Currently running an Apple iMac
OS 10.6.8
*please see attached screenshot for a reference

(1) Check names of all other devices on the network, including the router, any airport express, iphone, ipad, printers etc. Make sure these all have unique names.
(2) Do you have both wired ethernet as well as wireless active on any of these devices, including the Mac computer? This has been linked to such renaming behavior in the past, apparently the two methods of accessing the internet, if both are active at the same time, may switch off and on and conflict with one another (shouldn't happen, but apparently does sometimes). Solution is to switch one of them off.
(3) The following may be helpful:
In System Preferences > Network > Airport > Advanced > TCP/IP
Set "Configure iPv6" from "Automatically" to "Off".
If you do this, check to make sure that your email and other tools are still working properly. If something goes amiss, change the iPv6 back to what it was.
(4) Go to your router and reset power to it.
(5) Go to your router and check its LAN client table. Make sure that all entries should be there. Investigate any "extra" devices on the network. For instance, if it shows 4 devices, but you know you have only a computer and a printer, investigate what the other two are. Delete them from the list if they really seem to be "ghosts."

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This computer's local hostname is already in use on this network the name has been changed to

I've been getting this error after waking my computer from sleep. I think it has to do with my airport extreme. Does anyone have a fix?

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.

This computer's local hostname is already in use. How can I fix this?

Almost every day the following message appears in a pop up box.
This computer's local hostname "my-iMac-6.local" is already in use on this network. The name has been changed to "my-iMac-7.local"
The numbers do not correspond to those in the name in the Security preferences.
I preformed the "fix" described in the discussion.apple.com/messages---/messageID=9113111.
Set "iPv6" from "Automatically" to "Off" in both Airport and Ethernet.
That is apparently not the answer either.
There is only one computer in my house with the name shown in the message.
My wife's iMac has her name in it. Mine has my name in it.
How can I fix this?
Thanks for any help you can provide.
Rob Morrison

This seems to be a DHCP issue when the lease is renewed
When the computer reconnects (renews the lease) it believes its own computer name "already has been taken" so because the router has retained it on the local network so your computer inserts the after its computer name a
"-2" then a "-3" then "-4" etc. (the mac needs to do this and does so by default to ensure and create its own unique name on the local network)
-> this appears to be a delay / hangover on the router (AE or TC) when using DHCP
have seen a fix which only requires you set your computer with a fixed IP address
(can be EITHER reserved on the router OR set on the computer itself in network settings)
Router (AE or TC) Airport Utility 5.6 / Internet tab / DHCP button / click the "+" button & you reserve the computer's IP address by EITHER its MAC address (= shown in SysPrefs/Network/Advanced/Hardware) OR a DHCP client id (which you choose yourself) & enter exactly the same identical passphrase on the computer in sysprefs/network/advanced/DHCP(->set ro "using DHCP") shows textbox to enter the DHCP id
THEN apply with Update button (Router restarts)
Computer itself - under sysprefs / network -> Configure IPv4 to "Using DHCP with Manual Address" (will autofill from DHCP) check correct local IP address of computer is set & click Apply OR "Manual Address & manually enter the settings for local IP Address of computer / subnet mask / router's Ip address / DNS server's IP address / (DNS) Search Domain (optional)
Since setting static address this problem has not re-occurred.
Thanks to MacFixit there is a terminal fix here (from Sept 09) as well : http://reviews.cnet.com/8301-13727_7-10362633-263.html?part=rss&tag=feed&subj=Ma cFixIt

Local Hostname is already in use on this network

Hi,
Since upgrading to OS X 10.8 and then 10.8.1, I receive the following message when waking the iMac from sleep, "This computer's local hostname (see screen shot below) is already in use on this network". Earlier today, I went into the "Sharing" properties and changed the hostname to ShaneiMac and as you can see from the screen shot, it just renames it with a -2. It doesn't appear to be causing any issue in regards to performance of the machine but it's getting annoying. Is there any way to fix this?
Thanks.

Then this fix may work for you!
Warning, this may break your ability to use back to my mac.
Open Network preferences, select your network port (Airport or Ethernet) and click on the Advanced button. Click on the TCP/IP tab and set the Configure IPv6 drop down menu to Off. If you use both ports then make the same change for both ports.
Open Sharing preferences and reset your Computer Name.

New behavior: Computer's local hostname is already in use...

Recently when waking my Macbook Pro I get the following dialog...
...there is no other computer on the network with the same name. This is new behavior, what would cause this dialog to appear?

Yes this has been plaguing me since the 10.5.8 update. I found the following, I don't know whether it fixes this problem but it certainly doesn't cause any harm as far as I can see.
http://www.elharo.com/blog/mac/2005/11/29/setting-a-permanent-host-name-in-mac-o s-x/
It involves editing /etc/hostconfig. Do this at your own risk.

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.

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

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

This computers local hostname is already in use?

I turned on my computer this afternoon and was met with this message:
"This computer's local hostname "Name of my hard drive.local" is already in use on this network. The name has been changed to "The name of my hard drive-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."
Can anyone tell me why is this happening? I've never seen this before. Has my computer been compromised?
Thanks

Sorry--I missed that first time around. I think you would do better by reposting in the Forum for OS10.5. You have a software issue and that forum will have more software gurus. Machine-specific forums are better for hardware issues, but I think your hardwre is probably fine.
If you wish, I can ask the Hosts to move this for you so you need not do anything. Let me know.
OSX 10.5 forum is here:
Mac OS X v10.5 Leopard

"This computer's local hostname changed".

Since installing Mountain Lion, I have twice received the following warning pop-up. "This computer's local hostname "my-name-iMac.local" is already in use on this network. The name has been changed to " my-name-iMac-2.local". In both cases the hostname is automatically changed by adding a "2" at the end. I am able to go into "sharing preferences" and change it back, however I am confused as to why this is happening on its own.

Sometimes your network router thinks your computer is still connected to the network when it isn't - most typically after a forced quit or restart but not always. I've also seen it associated with a computer going to sleep and waking up. When your computer restarts or wakes up it connects to the router and the router, in human terms says, "No that can't be. I already have a Jim here. I'll call you Jim-2."
It is slightly aggrevating but no big deal. You may solve the problem (at least temporarily) by turning off every device on your network including the router and then turning the router on again - followed by the rest of your devices.

I'm trying an email address i know is mine yet still getting this message:"That Apple ID is already in use.If this Apple ID was created by you, simply sign in with your Apple ID and password.If it does not belong to you, try again using a different name."

I keep getting this message: "That Apple ID is already in use.If this Apple ID was created by you, simply sign in with your Apple ID and password.If it does not belong to you, try again using a different name."
I'm trying to create a new id and e-mail using an e-mail address that is mine and has been mine for over a year - any ideas why this could be happening?

Trying where? What sort of email address? The following answer is based on a guess as to what you are talking about.
If you already have an @me.com address, perhaps as a result of having had a MobileMe account, and you are now setting up an iCloud account with an Apple ID you will find you will be asked to create a new @me.com address, and that you can't add your existing one because it is already an Apple ID.
You can do one of two things:
1. Sign out at System Preferences; sign in with your existing @me.com address and enable Mail.
2. Stay signed in with the present ID and add your @me.com address in System Preferences>Mail, Contacts & Calendars.
If you have further questions, or if your situation is different from what I've assumed, do please post back, but in a suitable forum - this one is specifically about using these Forums.

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.

Why does my imac all of a sudden start changing "this computer's local host name"

why does my imac all of a sudden start indicating that "this computer's local hostname is already in use on this network" and then change the name

The default of the pref network.http.max-connections has been increased from 30 to 256 in Firefox 6+ versions.
Try to decrease the value of the pref <b>network.http.max-connections</b> from 256 to 30 as used in Firefox 3 versions.
*https://support.mozilla.com/kb/Firefox+never+finishes+loading+certain+websites

My computer's local hostname keeps changing - is there a solution?

I have looked into this in the community but have yet to find a resolution to this. I don't think this is a serious problem, but what do I know? The message that pops up is:
This computer's local hostname "besMac-277.local" is already in use on this network. The names has been changes to "besMac-400.local". To change the local hostname, open System Preferences and click Sharing, then click "Edit" and type the name in the Local Hostname field.
Screenshot:
The only think I can gether from reading the other posts is that having a wired ethernet connection to the router and wifi active may have something to do with it. I'm hesitant to unplug the ethernet as I would like it as a backup in case the wifi fails.
Thanks for your help!

I upgraded to Yosemite. Finder stays open and has a spinning wheel. It does not respond to Force Quit. I have spent 2 hrs. with Apple Support today on the phone. We tried to re-install Yosemite, but the time for completion started at 166 hrs. And kept increasing. So they are sending me to an Apple Store Wednesday. Others have commented on Finder problems.

This computer's local hostname is already in use on this network

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