iMac won't connect to wifi

Hello !

Please hold option key and click on wi fi icon

( a) open wireless diagnostics , take cursor to top left menu bar select open external tool.

Click on network diagnostics

select location

Then , click on continue network diagnostics window will appear

Again click on continue and follow the steps finally click on quit .

All network status must appear as green .

Suggested article : OS X El Capitan: Use Network Diagnostics

Thanks !

Can you give some details what settings are there on DNS , wifi security- WPA2 personal AES , etc .in network .

suggested article : Use Wireless Diagnostics to help you resolve Wi-Fi issues on your Mac - Apple Support

Not sure how well this will work but this has solved many of my problems:

Does your Mac have an Ethernet port? Try that directly with WiFi off and Ethernet -> DHCP enabled in network settings. If your Ethernet doesn't work, be sure you're doing it right. If you still don't have connection, you might have no internet. If you do:

Have you tried resetting SMC?

Reset the System Management Controller (SMC) on your Mac - Apple Support

Also, the latest OS is macOS Sierra in the app store:

https://itunes.apple.com/us/app/macos-sierra/id1127487414?mt=12&ls=1

EDIT:

Glad to see it was solved! Best of luck with your internet.

The blank IP addresses indicate, for some reason or another, your iMac is unable to find a DHCP server when connected by wireless. However, you also mentioned that even when connected by Ethernet it is slow. Both of these would indicate a potential hardware issue still exists with your iMac. Whether or not, it was introduced when you had the graphics issue resolved is unknown at this point.

I am going to assume that Wi-Fi is your preferred network connection so we are going to try some troubleshooting along this line.

Try the following on your Mac in order, until (hopefully) resolved:

1. Create a New User Account
   • System Preferences > Accounts
   • Click "+" to add a new account.
   • Log off, and then, log back on with the new user account.
   • Try connecting to your Wi-Fi network.
   • If this resolves the problem, there may be something amiss with your current profile and will require further troubleshooting.
   • If this does not resolve the problem, go ahead and log back into your normal account and go on to the next 3 steps.
2. Delete AirPort Keychain Entries
   • Launch the "Keychain Access" application located in Applications/Utilities.
   • In the windows on the left side: Select login for Keychains and "Passwords" for Category.
   • Click on the "Kind" filter at the top, and look for any "AirPort network password" entries...and delete them.
   • Close Keychain Access.
3. Delete Preferred Network(s)
   • System Preferences > Network > Wi-Fi > Advanced > Wi-Fi tab
   • Delete all entries under "Preferred Networks."
   • Click on OK.
4. Add Preferred Network(s)
   • System Preferences > Network > Wi-Fi > Advanced > Wi-Fi tab
   • Add the preferred network(s) using the "+" button.
   • Click on OK.
   • Restart or log out, and then, back in.
     • If it works, then you are done.
     • If not, go on to the next step.
5. Move System Configuration Files

I have since tried and successfully connected my iMac to my Samsung Galaxy phone mobile hotspot! Im not sure what this means but it is lightening quick to load web pages again.

A "hotspot" basically is a Wi-Fi network that is provided by your cellular carrier. The Galaxy, in this case, is using your cellular data network for Internet access, and in turn, creating a local Wi-Fi network for your iMac to connect to.

What this means is that the issue is not with your iMac's Wi-Fi but with your router, modem, or Internet Service Provider (ISP) connection.

If I had to guess, the issue is the DNS servers that are being used for this connection. Think of DNS as the Internet's Yellow Pages. By default, the DNS servers that you use will be provided by your ISP through the Internet modem. When you connected your iMac to the hotspot, you used the cellular provider's DNS servers. This could have made all of the difference in performance.

One option is to change these servers to another source, like Google or OpenDNS.

How do I move it instead of copying it? Ive tried right clicking but there is no option to move it?

Hold down the Command key, and then, click on the folder and drag it.