I have an Apple M1 MacBook Pro running Ventura. A few days ago I did a factory reset of my Macbook and reinstalled macOS due to an issue with my computer lagging. Yesterday I logged into Eduroam WiFi, and today when I opened up my laptop from sleep mode (I was on the same Eduroam network), I received a random popup that said the following:

This computer's local hostname "----Macbook-pro.local" is already in use on this network. The name has been changed to "------Macbook-Pro-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.

Please advise if the factory reset caused this issue since I am using the same network that I used before the reset. Interestingly, this popup did not appear when I used my home wifi. I also read somewhere that there could be some unauthorized access into my computer, but I spoke with an Apple advisor who dismissed that issue.

Any advice would be greatly appreciated.

  • 1
    FWIW, a factory rest is sufficient: reinstalling the OS is very rarely likely to fix anything.
    – benwiggy
    Mar 31, 2023 at 10:09

2 Answers 2


This has been frequently observed, even when no other similarly named Macs are on the network, usually as a result of DHCP caching.

Most reports suggest that turning off "Wake for Network access" in System Settings > Energy Saver will fix it (after correcting the name).


If you never changed your computer's name & are on a public WiFi, then it's extremely likely that at some point you'll find someone else with a similar computer on the same network who also never changed the name. This only becomes slightly less likely if you call it 'BobsMacBookPro'. Imagine how many MacBook Pros are likely to be in an educational establishment. You can't have two computers with the same name on the same network.
Result - one of you will have to be renamed to prevent clashes.

You can set any name you like from the Sharing prefs pane.

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Late thought - this is even more likely with Apple's new MAC address randomiser. As you preset a different 'face' to the network each time you connect, you could be seeing the system caching your own connection from last time - under a different address.

  • 2
    There are lots of cases of Macs spontaneously incrementing the name, even when no other computers are on the network.
    – benwiggy
    Mar 31, 2023 at 10:03
  • 1
    It only needs to report back 'name in use' & the Mac will increment. There's nothing particularly weird about a collision-avoidance structure being a bit eager.
    – Tetsujin
    Mar 31, 2023 at 10:04

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