iMac not seeing 5GHz Wi-Fi on macOS, but everything's fine on Windows

Question

iMac not seeing 5GHz Wi-Fi on macOS, but everything's fine on Windows

I have an iMac 27 mid 2011. The OSes that I have are Sierra and Windows 8.1 (via Boot Camp).

When I open the Wi-Fi menu on macOS, it doesn't show me any 5GHz networks, but when I boot into Windows, it works fine. When I try to connect manually (as if there was a hidden SSID), it fails to connect.

This clearly isn't a hardware problem (since Windows has no issues with 5GHz Wi-Fi), so I wonder if anyone has expected similar stuff on their devices.

P.S. I had to choose "iMac Line (2012 and Later)" as device because there wasn't a choice for older iMacs

iMac Line (2012 and Later)

Posted on Sep 4, 2019 5:21 AM

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Answer 1

Top-ranking reply

Eric Root

Level 10

684,591 points

Sep 4, 2019 7:42 AM in response to nick.karamoff

What does Wireless Diagnostics show?

Wireless Diagnostics

Try setting up another admin user account in System Preferences/Users & Groups to see if the same problem continues. Please post back on whether or not this worked. Also try the Safe Mode. Please post back on whether or not this worked.

Isolating an issue by using another user account

Safe Mode - About

If it works in the Safe Mode, try running this program when booted normally and then copy and paste the output in a reply. The program was created by Etresoft, a frequent contributor. Please use copy and paste as screen shots can be hard to read. Click “Share Report” button in the toolbar, select “Copy to Clipboard” and then paste into a reply. This will show what is running on your computer. No personal information is shown. If the log won’t post, try posting it in Pastebin and provide a link in a reply. After pasting the report in a PasteBin page, go to the top of the page, and copy the address in the URL bar. Paste that in a new reply. Pastebin

Etrecheck – System Information

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Answer 2

Eric Root

Level 10

684,591 points

Sep 11, 2019 7:46 AM in response to nick.karamoff

Booting into the Safe Mode is a very slow boot.

If you have the WiFi signal in the menu bar, click on it, and select Join Other Network. Then click Show Networks. Does it show there? Have you tried restarting/resetting the router?

Try running the combo update. It installs all previous updates plus the new one, which can replace any files that may have become corrupted.

macOS Sierra 10.12.6 Combo

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Answer 3

Sep 12, 2019 7:47 AM in response to Lexiepex

My home network also has separate SSIDs for 2.4 and 5 GHz.

Now something funny happened. I switched my Mac's language to English, so that everyone could understand the screenshots better, restarted the computer (it asked to) and oh well — the 5 GHz networks are back. No idea what is causing this. I plan on investigating more.

Here's what Option-clicking my Wi-Fi icon shows now:

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Answer 4

Sep 11, 2019 4:38 AM in response to Eric Root

Wireless Diagnostics didn't show any 5GHz networks to diagnose and my 2.4GHz network works just fine.

Logging into a new admin user didn’t do anything too.

When it came to Safe Boot, it took around 20 minutes to boot, idk if it’s normal or not. Anyway, there were no 5GHz networks.

I also gave “System Information” a look and it showed me that only channels 1-13 and 802.11a/b/g/n were supported. When I booted in Safe Mode, it had some additional 5GHz channels, but there still was no 802.11ac support, so it didn’t show my network.

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Answer 5

Lexiepex

Level 6

14,102 points

Sep 12, 2019 7:17 AM in response to nick.karamoff

Hold the Alt/Option key while you select the WiFi icon on your menubar above?

The name of the 5GHz and the name of the 2.4GHz net are probably the same, and the strongest of the two is automatically chosen. You can by hand switch to the other in the list.

Myself, I have named the two different like "Home" and "Home5G", you have to do that by logging in into the modem.

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Answer 6

Lexiepex

Level 6

14,102 points

Sep 12, 2019 8:21 AM in response to nick.karamoff

French is no problem at all for me I spend many months per year (20 years already) in France, but may be not for everybody.

At this moment you are connected to 5G (good signal/noise ratio, for FR even a respectable speed 108Mbps (haha).

Do you see the 2.4G also, it seems you have blocked that out in your picture.In the modem you can set different names for both speeds.

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Answer 7

Sep 12, 2019 9:24 AM in response to Lexiepex

I'm not from France, I am from Russia :D The FR code is there because my router's mode is set to "Europe", and I guess France is the central point Europe.

The one the second red arrow is pointing to (N....WiFi) is my 2.4G network name. Previously I could only see that name, but now I also see the 5G network (N.....5GHz) too. No idea why it appeared now and why it didn't appear before