344      iPhone_iPad_Mac_apple

MacBook Pro Sierra cannot connect to wifi network

Hello, Mac OS X Sierra 10.12.6

My brand new MacBook Pro is not connecting to my home wifi network. I have had this network for years with numerous devices, and currently with two other Apple devices. Also, it was working with this machine for several weeks without any issue.

Suddenly now, it is not able to connect. It is hanging endlessly and when I disconnect/reconnect, or restart the machine, I get the dialog box "The Wi-Fi network "..my network name" could not be joined." This began last night.

Then this morning it was working for about fifteen minutes, then stopped and gave me the "...could not connect..." window."

So, it is working briefly but then stops. I run diagnostics which basically tells me nothing.

Trying to troubleshoot what the heck is going on here. Thank you for any guidance.

What does Wireless Diagnostics show?

Wireless Diagnostics

Wi-FI connection drops

Wi-Fi Problems in OS X Yosemite

Wi-Fi Problems in OS X Yosemite (2)

Wi-Fi Problems in OS X Yosemite (3)

WiFi Potential Temporary fix - Yosemite

Also try turning off Bluetooth.

If your Wi-Fi source is capable of generating a 5 GHz Wi-Fi network, try that to help avoid conflicts with Bluetooth.

Ok thanks for the help. The connection seems to establish briefly when I reboot, but then it drops again. So it's intermittent but overall not connecting.

Turning off Bluetooth has no effect.

Diagnostics only offers a generic and vague response. Nothing actionable for me to try.

It wants to create a diagnostics report which is located in /var/tmp which I have no idea what that is. It's asking me if my router is in a closet, etc... I don't see how this is helping.

Thank you for the links, I will read up. Problem is since my computer won't connect my iPhone is rather cumbersome for troubleshooting.

Guess I can't edit my response above. Just an update...I found the diagnostics report generated, though I don't know what to do with it.

The diagnostics test seems useless - it just monitors your wifi and tells you when you disconnect, great I already know that. There is no problem with my network as this machine was already connecting fine for a while, and I have other devices connecting properly. The diagnostics offers no specific troubleshooting pertaining to the network settings on my machine, as far as I can tell. "Try rebooting your computer" is not helpful troubleshooting for a diagnostics report. I don't understand the usefulness it at all. But of course I may just not know.

You are welcome.  Try restarting your computer and your router. Sometimes, reset work.

The problem is with how mac manages network settings, in particular, but not necessarily, with change in network. For example, you might observe this issue when you switch form your workplace wifi to your home wifi. Note: This happens to me even when I had not changed the network.

Ideally, whoever programmed Mac, should have done an efficient job at flushing out the cache of network preferences/profile when a user switches to a different network. But, alas, I do not think you can expect that for a $7k machine any longer.

Strangely, it happened to me around the same time you logged in your report here and it ruined my entire day. I had not even switched between networks since several days before Christmas.

Ok, here is the solution:

Go to Network preferences. Under "Location", you'd have "Automatic" selected by default. Click on the drop-down menu there and click on "Edit Locations". Add a location with the label "Home". Feel free to add a few other locations such as: "WorkWifi", "HomeWifi", "Work3G", "Home3G".

On the left side pane of the same window, you'll see the different kinds of network interfaces: "Wi-Fi", "Thunderbolt..." etc.  Click on the settings wheel at the bottom and "duplicate service" for "Wi-Fi" so that you can have one service labelled as just "Wi-Fi" or "Wi-FiHome", which you can use at home and another service labelled as "Wi-FiWork" and you'd use this when at work. May be even add one more and label it as "Wi-FiPublic" for when you use Wi-Fi in a public library/coffee shop etc.

It is the combination of these two settings that control how your system connects to a network. In an ideal world, you wouldn't need even different locations, let alone duplicate/triplicate each service. That is unless you wish to use a specific configuration and override the default. For example, at work, you might want to use Google's DNS instead of your office DNS. 

Now, on the left pane, you can also change the order of connectivity by moving the services up and down. If you are now at home, choose the combination of Location "HomeWiFi" and Service "Wi-FiHome". Click on "Turn Wi-Fi on".Enter the Network name, your SSID. If your SSID  isn't hidden, it will include the name in the list of identified SSIDs automatically and you can just select the one that is yours. Type in the password to connect.

Then click on Advanced, under Wi-Fi tab, make sure you have the correct security type chosen. Here, tick the checkbox "Remember networks that this computer has joined". What this does is, once you connect to wi-fi at your work, the SSID of your workplace Wi-Fi will be displayed under this tab. You can drag and move the order of preference of network. You can use the "+" and "-" for adding a new network etc.

Also, click the checkbox "Turn Wi-Fi on or off".

Then, TCP/IP tab: Usually, in most networks, the IPV4 is obtained by DHCP request. But you are also able to configure a static IP if you have one at your work or if you want to reserve the local IPV4 address assigned to your laptop so that it doesn't get something else assigned to it (if you want static IP assigned to your laptop, make sure you set that in your router/modem as well. Your laptop will be identified by the mac address of the wifi interface on your router. Set its corresponding local IP in the router as well)

As for IPV6, again, usual configuration is to obtain automatically.

Go to DNS tab, again, at home you might want to use your router's gateway as DNS. But perhaps at work, you might want to use google's DNS (usually done to bypass some poorly configured restrictions that limit traffic based on DNS request alone).

Under Proxies tab, you can configure your web proxy, socks proxy etc. At home, you probably wouldn't use any. Just for fun, see if and what proxy settings your wifi obtains when you connect at work.

Under Hardware, you can set MTU/maximum transmission unit (which is usually automatically set to 1500). You will very rarely, if ever, need to change this. One situation is VPN to your workplace form home. Suppose, say your workplace has a sloppy network admin who has either set a limit on MTU of incoming requests or set a very low TTL (Time to Live), in such cases, you might want to set the MTU manually and lower the MTU to say 500 or 1000 bytes.

Click "Ok" and "Apply" and similar buttons once you finish doing all these.

Then, go back to network settings, click on advanced and then TCP/IP tab. You should see that if you chose to obtain IP address via DHCP (instead of static IP), you should see that your laptop now has a private IP assigned, with its subnet mask and Default gateway (router) address.

Once you have all of these, when you move your laptop between places/network, click on the corresponding combination of Location and service. For example: Location: HomeWi-Fi, Service: Wi-FiHome; Location: WorkWi-Fi, Service: Wi-FiWork" etc...

Since you already have organised these settings and isolated them, you should not have to restart your laptop just because you got back home from work. Unless, like yesterday, for me, this problem happened eventhough I hadn't moved anywhere. In that case, reconfiguring all of these followed by a restart was what was required to flush the cache..

All these because, someone couldn't care less to write efficient program.

It is quite late here and I note that this is very detailed. Ideally, I'd have organised under different headings, but unable to do so now.

If you have any questions, feel free to ask and I will try and check here to respond.

***************************

Additional point:

-------------------------

Oh, btw, if you intend to use Wi-Fi in public places, or even at work, go to "Security and Privacy" settings, Click on Firewall tab, Click on the lock button and type your password to allow you to make changes, Enable Firewall and tick the checkbox for "Stealth mode". You do not one some malicious/moronic software/person flooding your computer with an indefinite broadcast ICMP messages. This will block all ping packets. You will leave this unchecked only if you want ping packets to be sent through, which is when you are setting up your own network topology at home and conducting some experiments.

I hope this helps. Sorry about not being able to organise the material efficiently.

Goodnight.

LurkingShirkerOrShirkingLurker

最后更新：2018-01-13 21:43:35

  上一篇： Thumbnails not showing

  下一篇： spell check as I type stopped working