USB-C Hub

Hello, antoniofromthemead.

Sorry that you're having this problem with your new MacBook Air.

I suspect the hub is the issue. The obvious thing to do here is to eliminate the hub from the equation and see how the MacBook performs without it.

Can you use the external drive without the hub in place? If so, then run like that for a few days and see what happens. Then go back to using the hub and see what happens.

It would be easy enough to replace the hub if it continues to misbehave.

Also, you might reboot into safe mode and see if it helps. Let the Mac OS do drive directory repair, cache clearing and other misc housekeeping. Often just booting into safe mode and logging in, then immediately rebooting normally will resolve an issue.  You should do this with all your external peripherals disconnected but the keyboard and mouse. Press the Shift key until you see the Apple logo and progress bar when you restart you Mac.

Booting into Safe Mode… 

Use safe mode to isolate issues - Apple Support

Note– starting up in Safe mode could take 10 minutes or more. Be patient.

Does the problem persist while in Safe mode? 

Restart your Macintosh and re-evaluate the issue.

Log into another user account, Set up users, guests, and groups on Mac,  and see if the problem persists. (This tells us if the problem is limited to your user account or is system wide).

Boot into Safe Mode (Use Safe Mode to isolate issues with your Mac and Playing Safe: what does Safe Mode Do?) and check there to see if the problem persists. (This tells us if there's any 3rd party software that might be contributing to the problem.

NOTE: Safe Mode boot can take up to 10 minutes as it's doing some system cache cleaning, volume verifying and directory repairing. 

antoniofromthemead wrote:

...The Wi-Fi works perfectly until, I connect the Hub.

...The problem is inconsistent, which makes it difficult to identify.

...Furthermore, when I tested the hub at the local Apple Store it worked perfectly for an hour.

So it could possibly be my Wi-Fi provider but they blaming the hub because when it's NOT connected, the Wi-FI works OK.

What's the possibility that my LTE Wi-Fi Router which is close to my laptop, could be interfering with hub?

You did not have a wi-fi problem until you acquired this hub.

Inconsistent problems are the worst to troubleshoot.

While you say the hub worked fine for an hour at the Apple Store, were you testing your wi-fi router at the store?

If I were your wi-fi provider I'd blame the hub, too, because as you say the wi-fi was fine before that.

There's no evidence that the router is interfering with the hub. Your external drive still connects to and communicates with the MacBook through the hub. You aren't complaining about the performance of the hub.

In my view, the evidence is that the hub is causing interference with the network hardware or software in you laptop and/or router, or maybe even the wi-fi signal.

@Old Toad has put forth a couple very good suggestions for troubleshooting this issue. Follow that guidance and see what happens.

After that, here are some other troubleshooting steps you can try (some easier to accomplish than others):

• Position the router farther away from the laptop and the hub. Does the problem persist?

• Try using a different hub. Does the problem persist?

• Try using a different router. Does the problem persist?

USB 3 signals can interfere with 2.4GHz WiFi if the USB cables or hub are not properly shielded. Can you try 5GHz WiFi?