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iMac 27" keeps dropping Wi-Fi

About six months back I first started having an issue whereby my iMac 27 5K will periodically lose its Wi-Fi connection and get stuck in an endless loop trying to connect. When this happens the network services process uses up nearly all of my CPU and my system is unresponsive while the bars "search." Restarting has no effect - the Wi-Fi symbol in the menu bar continues to "search." Restarting the Mac, the access point and the router all have no effect.


Opening the network control panel takes FOREVER to open or respond and only rarely allows me to actually turn off Wi-Fi so that I can remove it and re-add (toggling off from the wi-fi symbol in the menu bar has no effect). IF I can complete this process it sometimes works for a few hours before the problem resurfaces (invariably in the middle of a Zoom call or some other critical setting).


The iMac has no connectivity issues when plugged into to an ethernet adapter. Unfortunately that is not a permanent solution as my office is in a location that cannot be hard-wired.


I've exhaustively searched for solutions but have found nothing that solves the issue permanently. Invariably it returns after as few as a few minutes or as long as a couple of days. Things I have tried many many times so far, in various combinations:


  1. Restarting and zapping PRAM.
  2. Running in safe mode.
  3. Doing a clean recovery to the latest OS.
  4. Removing all locations and adding new, custom location. Then removing Wi-Fi service and re-adding. I've also tried doing this with all other services removed, bluetooth off, etc.
  5. Removing all known wi-fi networks and reconnecting only to the primary.
  6. Changing the DNS settings.
  7. Deleting the com.apple.network and associated preference files.


I am connecting to a EERO mesh network and have tried reconfiguring the mesh in a variety of ways - none of which seem to make any difference.


Any ideas on a possible fix?


Thanks in advance.


iMac, OS X 10.10

Posted on Oct 5, 2021 9:42 AM

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Question marked as Top-ranking reply

Posted on Oct 11, 2021 4:53 PM

Luddify wrote:

Further update: Wi-Fi will no longer turn on even after clean install of latest OS through recovery. I'm inclined to think this is a hardware issue with the Wi-Fi card. Anyone know the likely cost of a replacement?

No, but you can call the nearest Authorized Apple Service Provider and ask them. Since that model is still covered by Apple you can take it into the nearest Apple Genius Bar for a free diagnostic check.


Is the problem iMac close enough to the router to be able to connect to it with an ethernet cable?


Have you installed or run any "cleaning", "optimizing", "speed-up" or anti-virus apps on your Mac?


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5 replies
Question marked as Top-ranking reply

Oct 11, 2021 4:53 PM in response to Luddify

Luddify wrote:

Further update: Wi-Fi will no longer turn on even after clean install of latest OS through recovery. I'm inclined to think this is a hardware issue with the Wi-Fi card. Anyone know the likely cost of a replacement?

No, but you can call the nearest Authorized Apple Service Provider and ask them. Since that model is still covered by Apple you can take it into the nearest Apple Genius Bar for a free diagnostic check.


Is the problem iMac close enough to the router to be able to connect to it with an ethernet cable?


Have you installed or run any "cleaning", "optimizing", "speed-up" or anti-virus apps on your Mac?


Oct 5, 2021 9:50 AM in response to Ronasara

Thanks, but there are literally dozens of other devices on multiple platforms connected to the same router all without issues. Restarting and reconfiguring the router has no effect on the iMac connection issue. The same iMac has been connected to the same mesh and router for over a year without any problems until this issue first surfaced about six months ago.

Oct 11, 2021 1:14 PM in response to Luddify

Update: Thinking it might be a problem with the mesh network, I hooked up an old ASUS gaming router and tried connecting to that. That solved the problem for a week or so until a new one emerged: now the Wi-Fi on the iMac is off and won't turn back on. I'm trying yet another clean install using recovery in hopes that will fix the problem and then connect only to the non-mesh router. This is aggravating beyond belief - I just want the stupid Wi-Fi to work on the iMac like it used to (and like every other device I own)!

iMac 27" keeps dropping Wi-Fi

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