another mac issue :(

[Big Jim]

2017 27" imac running Big Sur
Wifi has suddenly disappeared. it says it is switched off, you can toggle it back on on the top bar (which does nothing in reality)but not inside network preferences.
no matter what we have tried it remains off in the network preferences panel and we are unable to connect to wifi.
Ethernet is working fine though
bluetooth (on the same card) is also working ok.

Have tried a variety of fixes
resetting SMC
booting in safe mode
deleting network config files / reinstalling
deleting wifi connection from network prefs/reinstalling
reinstalled the OS over the top

booted from an install of High Sierra we have on a USB stick.

None of the above works.
However the iMac has bootcamp and the adapter works just fine in windows
also worth noting I am currently in a Big Sur recovery menu and the wifi adapter is on and showing available networks.
EDIT, whilst watching the wifi in recovery menu it keeps randomly turning off and back on


is this bad hardware if it still works ok in windows ?

 

[Big Jim]

It appears to be intermittent in windows as well, pretty sure this is a card failure, have ordered replacement card for it

 

[Markverhyden]

Sounds like hardware too me.

 

[timeshifter]

It appears to be intermittent in windows as well, pretty sure this is a card failure, have ordered replacement card for it

Just replaced a drive in an iMac this week, I feel your pain having to open that behemoth and tape it back just for a network card. I’d be tempted to try / offer an external Wi-Fi adapter.

 

[Big Jim]

Just replaced a drive in an iMac this week, I feel your pain having to open that behemoth and tape it back just for a network card. I’d be tempted to try / offer an external Wi-Fi adapter.

It was a machine we sold and still under our warranty so not really an acceptable solution.
Opening them up isn't too much of a PITA to be fair, although its easier opening them up when they have the genuine "foamy" adhesive on them, our adhesive takes a little longer.
To be fair the job was easier than I thought it was going to be, I thought I was going to have to remove the logicboard to get the 2 screws out of the wifi card, but thankfully, although the wifi card slot is on the back of the board, the screws are on the front., so remove screen, remove right side speaker and the wifi card needs 4 screws to remove it.

Replacement wifi card sorted the problem anyway

 

[mattsnoddy]

Replacement wifi card sorted the problem anyway

Was going to say, you can also try a wifi usb adapter to test if the wifi network software stack is having issues. Glad you got it fixed!

 

[Big Jim]

Was going to say, you can also try a wifi usb adapter to test if the wifi network software stack is having issues. Glad you got it fixed!

we have some generic ones lying around that MacOS wouldn't play nice with, but in the end it started playing up in windows as well so it was almost a certainty that it was hardware related (especially since the wired connection worked just fine)