You can make a difference in the Apple Support Community!

When you sign up with your Apple Account, you can provide valuable feedback to other community members by upvoting helpful replies and User Tips.

Looks like no one’s replied in a while. To start the conversation again, simply ask a new question.

Mid 2011 iMac 21.5, MacOS High Sierra, WiFi/Ethernet failure?

Good morning everyone!


I purchased the in title mentioned iMac off of my cousin. I am not exactly sure why he was going to throw it out and I can't find out exactly since he is unreachable while being overseas. His family told me it was something to do with the keyboard and mouse. I have since purchased a cheap keyboard and mouse from the good ol' Walmart, erased the disk and reinstalled MacOS High Sierra following instructions found here.


Almost immediately while using the Mac, the wifi would lose connection to my router. It would then stop showing all possible wireless connections in the area. When this occurred, I attempted to use an ethernet cord which too would not work and the Mac wouldn't even recognize a cord was plugged in.

The only temporary solution I have found is to restart the Mac. After restart the wifi and ethernet port work for a short time and then fail out again.


I have since erased the Mac and reinstalled the OS as a clean slate, erased all other wifi connections and re-established with my router, compared network preferences with my MacBook which is connected to the same router, and other possible solutions found on the web.


A lot of the solutions I have found are on the part of the router it self, but with the Mac not finding any other networks, including my iPhone's hotspot, and the ethernet port won't work either I feel as though it is an internal issue on the end of the Mac.


I have not found another issue quite like this one in the community and have searched the internet for the past day now to no success. Absolutely any help and advice would be greatly appreciated.


MacOS High Sierra Version 10.13.6

iMac (21.5-inch, Mid 2011)

Memory 8GB 1333 MHz DDR3

Graphics AMD Radeon HD 6750M 512 MB


Thank you in advance,

Mark

AATW

iMac 21.5", macOS 10.13

Posted on May 5, 2020 7:58 AM

Reply
Question marked as Top-ranking reply

Posted on May 5, 2020 8:14 AM

Please do the following (yes, even if other devices connect okay in this order):


  • Verify the modem and router have up-to-date firmware. You will need to check their manuals for instructions
  • Restart Modem
  • Restart Router
  • Restart Mac
  • Retest


If the above fails please use https://support.apple.com/en-us/HT202663

Similar questions

15 replies

May 5, 2020 9:24 AM in response to MarkEdward89

Well, you may have discovered why your cousin wanted to get rid of the iMac. Just sayin'.


You could try resetting the NVRAM; doing so will not cause any problems and it may cure the network issue. To do this, when you start up your iMac, immediately hold down the Command (⌘), Option, P, and R keys. Keep holding them down until you hear a second startup chime. (Note, you should use a wired keyboard for this.)


It may or may not help, but it's worth a try.

May 5, 2020 2:43 PM in response to rkaufmann87

I have, and I am going through it again as I type this. I am currently using an Xfinity router, not sure if thats a problem for me. I am running the diagnostics again before going on the house PC and attempt to finagle with the router settings.


The wireless diagnostic summary reads:

Review WiFi Best Practices

LAN Connectivity Failure

Conflicting Country Codes


Under the LAN Failure, it states that I am connected to a wifi network that cannot communicate with my wireless router.


Any idea how I can fix that?


Mid 2011 iMac 21.5, MacOS High Sierra, WiFi/Ethernet failure?

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple Account.