WIFI drops when I connect external HDD to Mac Mini via USB

onespeedvelo

macrumors newbie
Original poster
Jun 2, 2015
25
30
I have a Mac mini 2018 i7 256GB storage and 8GB RAM. It runs Mojave. Very happy so far. I had to save money on the storage of course so I was lately running out of space. I sometimes connect my MBP on the network and use my other's Mac storage.

A couple of days ago I used an old HDD and plugged it in the USB port of the mini. I then forgot about it and did not give it a second thought during the whole day.

Long story short, my wifi connection was very slow on that day. To download a 5MB pdf would take 45 min to a few days (oh?). I option clicked on the wifi icon of my screen and got the speed under tx.. and it was 5 Mbps.

On the same wifi network on my old MBP I had 140 Mbps!

I tried everything. Restarting the Mac, unplugging replugging the router. I was getting mad. Could not believe that the low speed was affecting only my mini and not the other computers.
I started to believe I had to send it in for repairs until the wifi connection dropped completely and my mini could not recognise my wifi network or any other network in the house.

I spent the most part of the day trying to work with a low internet speed and trying different things to troubleshoot. Nothing.. until.. I unplugged the HDD! Immediately everything started working again.

I now understand that the HDD frequencies were interfering with the Mini wifi. But why on the mini and not on my 2010 MBP?

Is this normal? I tried again with another HDD and this time the Wifi network dropped immediately and got disconnected.
 

chrfr

macrumors G3
Jul 11, 2009
8,203
2,530
I now understand that the HDD frequencies were interfering with the Mini wifi. But why on the mini and not on my 2010 MBP?

Is this normal? I tried again with another HDD and this time the Wifi network dropped immediately and got disconnected.
Different computers have different sensitivities to wifi interference. If you can change your wifi network to use 5GHz instead of 2.4GHz, the problem may go away.
 
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Fishrrman

macrumors P6
Feb 20, 2009
17,216
5,558
As chrfr mentioned, try to use the 5ghz wifi band.

Another option:
If there is ANY way to run an ethernet cat5e or cat6 connection to the Mini, do it...!
 
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canyelles

macrumors member
Nov 8, 2011
38
16
I have had this same problem with a 2014 mini and a SSD in a usbc case connected with a USB3 converter.

Wifi didn't work at all after connecting the disk.

I was able to get wifi back by moving the disk as far away as I could from the mini
 
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