OS X keeps appending "(2)" to computer name

What Worked For Me

After trying everything suggested here and having that (5) coming back time and again here's what finally fixed the issue permanently for me on my 2009 MBP.

1. Turned my router off to ensure no connection to anything as well as unplugged my AppleTV's just for the hell of it.

2. Turned off Time Machine.

3. Went to Macintosh HD > Library > Preferences > SystemConfiguration
and deleted the following files:

com.apple.airport.preferences.plist
NetworkInterfaces.plist
preferences.plist

4. Emptied my trash.

5. Went to Settings > Sharing and deleted the (5) from the end of my Mac's name.

6. Restarted my Mac.

7. Turned on Time Machine and ran a back-up, preparation took a long time.

8. Restarted my Mac one more time after back-up completed.

9. Turned on my router, AppleTV's and re-connected my MBP to my router via wifi.

It has now been over a week as well as applying the 10.10.1 update and no return of that (5). I truly hope this helps someone else out, what a pain!

FWIW...this had been an issue for me since my clean install of Yosemite and I had tried a number of things found in this thread, nada.

Just this past weekend I decided to retry the initial suggestion:

Settings> Sharing> Computer Name... deleted the (2) append and hit 'Enter' with some extra oomph.

2 days an counting... still 'Jason's iMac'. No append. Maybe it was a silent fix from Apple?...

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Thinking back on it...this weekend I also changed my DNS servers too (to OpenDNS, unrelated to this). Hmm...

I think Apple fixed it with 10.10.1. But you have to turn off your router, remove the (2) from your computer's name while the router is off. Then put your Mac to sleep and restart the router. Worked for me with 10.10.1.

They didn't fix it......read the thread here about the 10.10.1 release....plenty of folks seeing the issue

andrewcfreels said:

It has now been over a week as well as applying the 10.10.1 update and no return of that (5). I truly hope this helps someone else out, what a pain!

Click to expand...

The problem has been gone for 4 days now - my MBP was up to 28 when I'd change the name and trash the preferences. Did a lot of other stuff, too, but I think it was the preferences that did it. - But I still have my old computername listed from number 2-27 under Shared in Finder Sidebar. I should very much like to get rid of them....

There is one thing I remember when this problem showed up. After sleep I'd often get the message that there was another computer on the network using my IP. No problem to connect to Internet after that, but I think that explain the changing of name. My network is wi-fi with 2 Apple Extreme ac and 2 Extreme n, plus a Thomson VDSL-router with wi-fi disabled. The Thomson is set to distribute IP-addresses. Here is a nice screenshot of what's in my shared items:

fhall1 said:

They didn't fix it......read the thread here about the 10.10.1 release....plenty of folks seeing the issue

Click to expand...

turn off back to my mac, wake for network access, sharing

change name of your computer to sometime else unique

restart router

change name back to your favorite

turn back on services

10.10.1 did not fix it for me. In fact, I am now having it on a computer that I didn't have it on before. Strangely, I am not using Wake for Network Access on this one and never have. This started today away from home with a wireless network I don't control. I'm sure they do not use Apple routers. Maybe this is a related problem but not the same thing? Maybe someone else actually has the same computer name as me?

With another computer, the one I was having trouble with, I did a clean install of Yosemite and left Wake for Network Access off. It has behaved so far. After installing 10.10.1 yesterday, I turned Wake for Network Access back on. We'll see, but I'm not optimistic.

In my usual setup, I have an AirPort Extreme as the main router with two AirPort Expresses set up as wired bridges. I have an Apple TV connected by Ethernet and an old, original Apple TV on wifi. A wired iMac has never had this problem, but my MacBook Pro has had it since originally installing Yosemite.

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kolvorok said:

The problem has been gone for 4 days now - my MBP was up to 28 when I'd change the name and trash the preferences. Did a lot of other stuff, too, but I think it was the preferences that did it. - But I still have my old computername listed from number 2-27 under Shared in Finder Sidebar. I should very much like to get rid of them....

Click to expand...

I have been able to get rid of my imposter computers in the Finder sidebar by trying to connect to them, either by file or screen sharing. I can't make the connection, eventually getting a "Connection Failed" message, and then they disappear from the sidebar. I do this after changing my name back to what it should be.

I was testing this just now but my name hadn't changed back (well, won't stay changed). It is very strange because I can now connect to the computer I am using as if I am on a remote computer. This is all starting to get a little creepy.

medgirl2001 said:

I have been able to get rid of my imposter computers in the Finder sidebar by trying to connect to them, either by file or screen sharing.

Click to expand...

This didn't work for me, I got the message (translated) "There was a problem connecting to..." for all of the 26 "ghosts". I then turned off all sharing, the items was still there, I turned off Wi-Fi - they dissapeared, turned on - they came back.

Restart or logging out/in didn't do any difference.

kolvorok said:

Restart or logging out/in didn't do any difference.

Click to expand...

Problem solved! I turned on "Back to my Mac" in System Preferences/iCloud and did the same for all of my 4 AirPort Extremes, updated them and the "ghosts" are gone...

This is still an ongoing issue for some. It even got some "face time" today on MacBreak Weekly podcast with Leo Laporte, Andy Ihnatko, Rene Ritchie and Alex Lindsay. Rene mentioned someone he knew had over 2700 instances of an AppleTV.

I seem to have fixed it by turning off Wake for WiFi. It’s been over 2 weeks now for me.

dfausty said:

I seem to have fixed it by turning off Wake for WiFi. It’s been over 2 weeks now for me.

Click to expand...

Could be it's not that simple. I had turned off "Wake for Wi-Fi", but when I activated "Back to my Mac" on the Apple base stations I was told to turn it on. The "ghosts" was gone after that.

kolvorok said:

Could be it's not that simple. I had turned off "Wake for Wi-Fi", but when I activated "Back to my Mac" on the Apple base stations I was told to turn it on. The "ghosts" was gone after that.

Click to expand...

I didn't mean to imply that it was simple. Like many, I’ve tried multiple things, and am currently working with a senior advisor at Apple, but so far this fix seems to be holding, at least for me for now.

dfausty said:

I didn't mean to imply that it was simple. Like many, I’ve tried multiple things, and am currently working with a senior advisor at Apple, but so far this fix seems to be holding, at least for me for now.

Click to expand...

Sorry, but I'll hope you read the word "simple" with a very light shade. For me there has been two problems in this tread: 1. The computer renaming by numbers and 2. The list of "ghosts" in Finder Sidebar/Shared.

My struggle was to get rid of the last - and it' solved as I posted previously. I've also managed to keep the name of my MBP after trying a lot of the solutions here, but I'm not shure what really did it. Could be that it's related to the AirPort software/firmware for what I know. It's just a guess...

kolvorok said:

Could be it's not that simple. I had turned off "Wake for Wi-Fi", but when I activated "Back to my Mac" on the Apple base stations I was told to turn it on. The "ghosts" was gone after that.

Click to expand...

"Back to My Mac" and "Find my Mac" still work without "Wake for network access", the Mac just has to be awake.

The joke is 1/2 the time "Wake for network access" fails to wake up the Mac anyway. It only really works well from your LAN.

BTW I ran with it turned off and the incrementing hostname problem stayed gone. Since the release of 10.10.1 I turned on "Wake for network access" and have had no issues. Now I did also restart the Airport Extreme so everything gets renewed.

Not sure if this has anything to do with it but how many Airport/Time Machine devices do people have when they're reporting (2), (3) and (4) etc added to their name? I have two and I always got a (2) added to my computer name.

I followed the advice of turning off "Wake for Wi-Fi network access" in Energy Saver preferences and the problem hasn't reappeared, but I also did the following. I have two Airport devices (2 x Express) with one as a master Wi-Fi and the other as a slave to extend the network (and provide AirTunes). I was logged in to Back to My Mac on both devices but I figured this wasn't necessary, so I logged out on both (in AirPort Utility), changed my computer name to remove the (2) and then logged back in on only the master Airport Express.

I don't know which of the above did the trick but I haven't seen the problem return since yesterday.

Can someone explain to me what Back to My Mac is actually necessary for? I use file sharing and screen sharing between my computers. It seems like that works without BTMM. I feel like the culprits in this problem are wake for network access and BTMM.

I win!

Submitted my image for the competition!!

Anyone ever tried deleting:

com.apple.airport.preferences.plist
NetworkInterfaces.plist
preferences.plist

From /Library/Preferences/SystemConfiguration ?

I just did, computer name was reset to default after reboot which i then changed back to my previous name. Can't say how long it will last. And i hope this won't mess up my Time Machine backups

http://apple.stackexchange.com/questions/153080/computer-name-keeps-changing-osx-10-10-14a389

neongrau said:

Anyone ever tried deleting:

com.apple.airport.preferences.plist
NetworkInterfaces.plist
preferences.plist

From /Library/Preferences/SystemConfiguration ?

Click to expand...

Yes: https://forums.macrumors.com/posts/20223516/
It seems to work for most people.

I have 5 macs here all running Yosemite and it only affects 1 computer and that is the only computer that connects via wifi.

Is wifi the culprit here?

The technical explanation is called ARP randomization and the Bonjour Sleep Proxy.

When scanning for WiFi Networks and requesting addresses via DHCP, there will be a short period where a the Bonjour naming systems believes that a device with the same nam but different MAC address is already on the network.

If you hardwire your IP addresses (you can use DHCP with static IP's) you will not have the problem.

I have set static IPs and I still get the problem on my laptop (connecting via wifi).

iLog.Genius said:

I'm at 9! WOO!!!

Click to expand...

I've got you beat, I'm at 178 for my 27" iMac and 9 for my 24" iMac...

Pagemakers said:

I have set static IPs and I still get the problem on my laptop (connecting via wifi).

Click to expand...

I don't ... and I'm not saying that I don't believe you.
It at least solved my problem.

Do you have an Airport Basestation or Apple TV that will act as a sleep proxy?
Do you share iTunes Libraries over WiFi?

My MacBook Pro was doing this, too, even though I set an IP via DHCP (static reservation).

The way I got it to stop was to turn off the "Wake for Network Access" option in the Energy Saver preferences.

I know some of you have said that hasn't worked - but I thought I'd chime in that it worked for me.