Hostname duplication

I've only seen it when there is definitely something on the network with the same name. AFAIK, you'll have to check all mounted volumes and their names.

I don't do wifi, so I can't address that. I do know that the only time i've seen it is when there's another device, usually another computer, having the same name. No phantom or hidden volumes or servers showing anywhere with that name?

Thanks for the feedback. Hope it doesn't raise its ugly head again. Good computing.

Hi , I have been having the same intermittent issue recently. I have an ethernet link to an airport extreme (running in bridge mode), linked to an ADSL modem. I suspect the problem is to do with the airport extreme. I have also been having intermittent IP clashes due to another device using the same IP address as my Mac and this appears to be the airport extreme as a scan sometimes shows the misbehaving device to have the same MAC address as the airport extreme. Recently this appears to be happening less often but the hostname duplication problem has started occurring instead. I always seen to be able to rename my Mac back to its usual name, so I do not think the abnormal behaviour persists for long. It sure would be nice if Apple could fix the problem.

I have been having the same problem regularly (several times a week) now for well over a month. Sometimes it happens so often that by the time I get to the computer (I'm often working on my notebook rather than my iMac) it's on number 5 or 6 in the chain!

I too have a sneaking suspicion that it's something to do with the Time Capsule I'm using as a router. I can't think what else would be causing this problem. Any suggestions or fixes would be welcomed - I recently made the switch from Windows and I'm not savvy enough in the new OS innards yet to dig around and find the issue myself.

Hi, same here. It happens several times a week with my mac mini which I also mainly use as a media player/server (running Plex). Usually the hostname changes when the mac mini wakes up. I have a time capsule and airport express in bridge mode (WDS).

One piece of information I might add to this discussion, is that I actually see that the hostname is not 'released' in the network environment when the mini is being shutdown or put asleep: on my macbook, the hostname remains visible in the network overview of the finder. I have enabled file sharing and screen sharing on the mini and sometimes the macbook is connected while I shutdown the mini. When it comes back up, the hostname changes (righteously I suppose) to (n+1) and I can then see both in the network environment. After a couple of restarts (computers and network devices, I haven't been able to pinpoint a single faulty device), the old hostname is finally forgotten.

Is there some expert who can explain why the hostname does not disappear? Where is it retained?
Is there a way to force a 'hard refresh' of the network environment?

The problem is annoying, everyone here will agree. Any help is greatly appreciated.

I just want to bump this thread up.
I'm having this exact problem and it's driving me completely nuts. All of my computers are set up to print through my tower via printer sharing. Every time the computer sees itself, and renames itself as a result, I either have to recreate the printer on the other computers or rename the tower to it's original hostname.

I haven't done extensive testing, but I have a feeling that this is happening when my computers (it happens to all of them) go to sleep on their own. If I put them to sleep, it doesn't seem to happen. I also have a feeling that it's Time Capsule/Airport causing this. I doesn't happen at my work where I'm using other network hardware, both with static IPs and with DHCP.
It's also happening to both my wireless & wired clients.

Hello, Apple? This is a huge, infuriating problem that's existed for some time now.

Same here: problem exists since some month now – my Hostname is already "iMac (150)" ...
It's very annoying when printing over the network ...
If i just delete the numbers of the Hostname, the problem returns after a few days.

I have no Time Capsule or Wireless-Network or any special device, just two computers (different machines with of course different, custom names), connected via Ethernet:

"myiMac(150)" <---> Fritzbox 2170 ADSL/Modem-Router <---> "Server(19)"

It seems "myiMac" (and "Server") sees, but does not recognize itself on the network?!

Is there any way to fix this problem?

tfranz,
if you're not using a Time Capsule or Airport Extreme, then there goes my theory. It must be something in the OS and how it deals with DHCP addressing. Since my last post, I turned sleeping off in energy saver, and I'm manually putting my computers to sleep. None of my machines have yet duplicated their hostnames.

Given this problem has existed for quite some time, it proves that Apple is too busy with iPhones & iPads to bother with old-fashioned OSX.

Thank you for your reply – indeed, it seems to be a problem with energy saver/ Apple support ...

Don't blame Apple.

Hostnames are resolved via Multicast DNS Service aka Bonjour...

Sometimes, your computer will send out it's hostname and it will get cached on the network and your computer will get disconnected for one reason or another (such as going to sleep or losing it's wifi signal)... When the computer reconnects, since it didn't release the hostname properly - it will detect that the hostname is already in use and add a (#) to the end of the name to remain unique.

If you're experiencing this issue, the first thing that I would recommend is to prevent your computer from going to sleep at all. See if that fixes your duplicate host issue and report back to us please!