MacBook won’t connect to internet - other devices do

[JML_UK]

Hi
Wonder if anyone has any suggestions as I’m tearing out what little hair I have left

I have a mid 2012 MacBook Pro running Mojave 10.14.6. There is 50gb storage remaining on a 500gb ssd and 8gb RAM

It connects fine to my wireless network, and airport utility shows a green light for internet - but it won’t connect to the internet - I get “could not connect to the server” or “could not open page” no matter what site I try

I have emptied cache and history and tried Safari and Chrome. I’ve turned off VPN, rebooted the machine and tried setting up another user - all with no effect.

I have a MacBook Air, an iPad and an iPhone, all of which are accessing the internet via the same Wi-Fi with no problem

I’ve checked the Network section in system preferences and can see no obvious problem in the ‘advanced’ settings and the settings mirror those on the MacBook Air that works fine (also running Mojave)

The only thing I can’t do is change the DNS - it seems to be nailed down by the router: the figure is greyed out and it won’t let me add extra by the + button. But that’s the same on the MacBook Air too (and same dns)

I should add the MacBook Pro has worked fine on another network

Any suggestions would be much appreciated

 

[ferrarr]

It does sound like something to do with your Wi-Fi network? Have you done a network power cycle? Power down everything, router, modem, and every device connected through the network like game consoles, set top boxes, printers, computers, “home” devices, etc.


Sent from my iPad using Mac-Forums

 

[JML_UK]

Thanks Ferrar - yes, I’ve done all that - and disconnected the other devices attached - no joy. I didn’t suspect the network though - the MacBook Pro’s wireless diagnostics reported all working as expected, and I’ve no problem with a MacBook Air, an IPad, an iPhone and an Apple TV box. (the only other devices on the network) which will all work together. It’s just the pro that accesses the Wi-Fi OK but can’t get on the internet, with other without the other devices connected.

Grateful for your thoughts though

 

[MacInWin]

The only thing I can’t do is change the DNS - it seems to be nailed down by the router: the figure is greyed out and it won’t let me add extra by the + button. But that’s the same on the MacBook Air too (and same dns)

That is not correct behavior. The DNS should be able to be changed. What happens when you try to add extra by the + button? Is your account an admin account? You have to be an admin to change network DNS settings.

EDIT: If you think the router is locking the DNS, turn off Wifi and then try to make a change. If you aren't connected to the router, it cannot "lock" the settings. But I'm betting it won't make a difference because something else is wrong in your network setup.

 

[JML_UK]

Hi MacInWin

No, I’ve never not been able to change DNS before, it does seem like strange behaviour - but I understand this is a result of my ISP locking down the router - I can’t change router settings either: they keep the admin password secret!

When I hit the + button a line off 0.0.0.0 appears - but as soon as I start trying to type, or if I do nothing for 10 seconds or so then it just disappears and reverts back to the original greyed out address.

But it does that on the MacBook Air as well, and that connects fine.

Grateful for your thoughts

 

[MacInWin]

There was someone else recently with that problem and I think he got sorted by running DetectX Swift to get rid of the hijacker. Let me look for that thread. BRB.

 

[MacInWin]

Here is that thread, but it may not help. His just started working again.

https://www.mac-forums.com/forums/m...onnect-wifi-internet.html?355832=#post1845879

You might try what I suggested in post #4 about stopping WiFI, make the changes, then turn WiFI back on. That way the router cannot block you because you are not connected to the router. I doubt the router could block you, anyway, as it is not authorized to make those kinds of changes, even if your ISP locks you down.

One other thought. Turn off your firewall on the Mac. You don't need it when connected to your home network. Just remember to turn it back on when you take the Mac to an alien network.

 

[pigoo3]

I have a MacBook Air, an iPad and an iPhone, all of which are accessing the internet via the same Wi-Fi with no problem...

I would say if these other devices are connecting to your home network via WiFi ok...then it's probably a computer based issue...and not a network issue. Don't mess with your network settings (router, cable modem, etc.)...or you may mess up WiFi for your other devices.

Two things I would try:

1. Try connecting this computer via ethernet...to see if the computer can connect to the internet ok via ethernet. By doing this you can test if you have a computer based Network Preferences setting issue...or a hardware issue (maybe soemthing is up with the computer's WiFi hardware).

2. Try creating a new user account & try connecting to the internet via WiFi. This new user account should have everything set at default settings...and you should have no interference from any other software installed on the computer. If you can connect to the internet via WiFi with the new account...then your main account could either have a settings issue...or a software conflict issue.

HTH,

- Nick

 

[JML_UK]

Thank you MacInWin, much appreciated- I’ll check that thread to see if there are any useful insights there

 

[JML_UK]

Pigoo3 - thanks for the thoughts - I’d already tried the additional user route to no effect - but the Ethernet connection suggestion is a good one - It hadn’t occurred to me because, as you say, indications are that the Wi-Fi is sound - but it’s well worth a try
John

 

[pigoo3]

... I’d already tried the additional user route to no effect...

Sorry about that...you did mention this in post #1. Good luck with the ethernet test.

- Nick

 

[ferrarr]

The only thing I can’t do is change the DNS - it seems to be nailed down by the router: the figure is greyed out and it won’t let me add extra by the + button. But that’s the same on the MacBook Air too (and same dns)

I should add the MacBook Pro has worked fine on another network.

When you go into System Preferences > Network, you may need to unlock the lock to gain access to change some of the settings.


Sent from my iPad using Mac-Forums

 

[JML_UK]

Hi Guys I think I may have cracked it

Found a suggestion in a thread about not being able to change dns that a corrupt plist might be the problem

Moved com.apple.systemprefs.plist to the desktop, rebooted - and hey presto I could then change the dns and I now have an internet connection that’s been stable for 15 mins or so

Another one to add to the file!

Thanks so much for your generous help

Take care all
John

 

[MacInWin]

Well done. Sorry none of us came up with that.

 

[JML_UK]

It’s a collective thing, MacInWin - it really helps talking through with other folk, and thinking it through. And learn something every time

 

[Ek- needs- help]

Hi Guys I think I may have cracked it

Found a suggestion in a thread about not being able to change dns that a corrupt plist might be the problem

Moved com.apple.systemprefs.plist to the desktop, rebooted - and hey presto I could then change the dns and I now have an internet connection that’s been stable for 15 mins or so

Another one to add to the file!

Thanks so much for your generous help

Take care all
John

Hello, I am having the same problem as you about not being able to change the DNS. Also Ethernet doesn't work either. I tried your solution by searching com.apple.systemprefs.plist in my mac but nothing comes up. How do I find this?

 

[Ek- needs- help]

Hello, I am having the same problem as you about not being able to change the DNS. Also Ethernet doesn't work either. I tried your solution by searching com.apple.systemprefs.plist in my mac but nothing comes up. How do I find this?

Update: I found the com.apple.systemprefs.plist and moved it to my desktop and rebooted. Still no luck with changing the DNS.

 

[MacInWin]

Have you unlocked the previous pane with your admin password? The DNS cannot be changed unless on the Network pane the lock is open.

 

[chscag]

Have you unlocked the previous pane with your admin password? The DNS cannot be changed unless on the Network pane the lock is open.

There is no lock on the Network pane. DNS has always been free to change without unlocking. Also many folks may not realize it but DNS can also be changed through your router setup menu if it is an item that is allowed. Some routers do not have that option..

 

[MacInWin]

Charlie, I would beg to differ, at least for Monterey. I just tested it and when I went to the DNS pane, it was greyed out. I had to go back to the Network page, unlock and then choose "Advanced" to get to the DNS pane unlocked.