Intermittent WiFi connection for 2019 iMac
February 26, 2024 3:43 PM   Subscribe

I have a 27" 2019 iMac (Intel). Every so often it can't maintain a connection to my home WiFi. It starts working again if I move it from the second story office (about 30' from the router) to a few feet away from the router (on the first floor), and after I return it to the office the WiFi connection is steady from any where from a few days to a few months. I repeat the temporary move every time the WiFi connection can't be make in the office. Any ideas what's going on?

Rebooting in place doesn't fix the issue (I've tried many times). Obviously, it reboots between moves as I have to unplug it and plug it back in.

Having it forget the WiFi point and reattaching while in the office doesn't fix it. The only fix I've found is the temporary move to right beside the WiFi router.

The iMac's logic board was replaced about 2 years ago via AppleCare+ (it was crashing intermittently). The WiFi issue only started about the replacement.

In the office, there are other devices connected to the WiFi, an HP printer, a Tablo TV recorder, and usually my iPhone and a MacBook. Removing them or turning them off doesn't fix the problem (this was testing if the issue was WiFi interference).

WiFi diagnostics don't show anything.

It's still under AppleCare+, so I could have it looked again, but given that when there's a strong WiFi signal it seems to work find and reset the issue, I'm not sure if a repair tech would find anything.

A possible workaround is to use an external USB or ethernet WiFi connection to the iMac. Or setting up powerline ethernet (although the office and the location of the router are on different power circuits, so I don't think that is doable).

Given that I can get it working after the temporary move, it's only annoying at the moment. But I'm curious if someone has an explanation.
posted by ShooBoo to Computers & Internet (11 answers total) 1 user marked this as a favorite
 
Generally speaking, something that only manifests after a while of computer being on, is very likely thermal-related (i.e. the Wifi is overheating somehow). This also tracks with rebooting doesn't cure it, but moving it between floors does (gives it time to cool down).

Have you tried turning off the computer when it happens, take a quick break, then try again, without moving it?
posted by kschang at 3:53 PM on February 26, 2024


Response by poster: Have you tried turning off the computer when it happens, take a quick break, then try again, without moving it?

Yes, I have shut it down overnight, and it still had WiFi connectivity issues when restarted the next day.
posted by ShooBoo at 4:02 PM on February 26, 2024


Next idea: no one ELSE has connectivity problems during that time, right?

There are IT legends of intermittent connectivity problems like this that that got traced to someone using the microwave during certain hours of the day.
posted by kschang at 4:32 PM on February 26, 2024


Every so often it can't maintain a connection to my home WiFi.

What does that look like? Dropped wireless connection? Can you see the network when you try to reattach?
posted by Tell Me No Lies at 5:08 PM on February 26, 2024


Response by poster: What does that look like? Dropped wireless connection? Can you see the network when you try to reattach?

It varies. The WiFi icon can go into its search mode. If a connection can be made, but it's slow, websites don't load fully and then Chrome says there no internet connectivity.

I've tried pinging 8.8.8.8 when it happens. In one ping session most pings fails, but some get a response.
posted by ShooBoo at 5:14 PM on February 26, 2024


I'm currently in a semi-residential area where some of my devices can see up to about 15 local WiFi networks at any time.

We find there's a lot of interferance on some channels (channels as set by the router WiFi point). So often switching to another channe frequency on the router resolves the issue (via the router console admin login).

Otherwise similar to as you describe, we technically have a strong bar signal of our network to each device, but some devices within that group (all with good signal strengths apparently) have extremely slow or intermittant connections. Others are slightly better. But still weirdly intermittant.

It seems like playing cat and mouse with the neighbours, as every few weeks it gets progressively worse again so we switch to a new frequency again (sometimes even the same channel we abandoned months before, that now works again).
posted by many-things at 7:14 PM on February 26, 2024 [1 favorite]


How many devices are connected to the router via Wi-Fi when the problems happen? Does shutting Wi-Fi off on one of them resolve the issue?
posted by TimHare at 9:50 PM on February 26, 2024


Does the problem go away if you pick the iMac up and set it down again without bringing it downstairs?

If so, it could be an issue with the internal wifi antennas.
posted by zippy at 11:49 PM on February 26, 2024


I'd definitely try Zippy's test, take it for a walk and put it right back where it started to see if it's possibly a physical connection inside. It's worth taking it back to Apple just to get it on record. Maybe a few service trips will get you some resolution.
posted by advicepig at 6:37 AM on February 27, 2024


Response by poster: Thanks for the suggestions. If anything works, I'll update this post.
posted by ShooBoo at 11:56 AM on February 27, 2024


I’ve seen something very similar, but it was in a different situation: the person had two Wi-Fi routers that were broadcasting the same network name (SSID) and one of the routers had been unplugged from ethernet. As a result, when computers were using the “good”router everything was normal, but when the computer decided to associate with the bad router, it would have many problems.

Is there any chance that you have a second Wi-Fi router that you have forgotten about? Or are you using a Wi-Fi network name that your neighbors could also be using?
posted by soylent00FF00 at 10:15 AM on February 28, 2024


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