Macbook Air will not connect to Wifi even though other Macs work fine with same Wifi

I'm having some issues and I feel as though I have literally tried everything. I am at a complete loss on what to do.

Situation:

I had multiple Mac computers including this one for a while. All working fine with router.

Then I replaced my router because it was getting slow and dated, the new one I got worked fine at first, but then started to drop connection every other day and even sometimes every day. I replaced the replacement router, then my macbook air had ridiculously slow connection speed. It would take google 5-10 minutes to load. But my iMac computer worked fine. I didn't change anything, nor do anything different to either computer except get this new router. The router even managed to corrupt my time machine. So I called up the ISP and they worked me through the issues, so now everything is working fine EXCEPT my Macbook Air.

I have tried starting from scratch with the router, with the Time Machine, I have rebooted all devices. But the internet remains the same. It's good on my iMac, my phone, my TV, but not the macbook air. I wanted to call Apple, but it costs $60 to talk to a someone which is not affordable for me. I am really frustrated with this.

I went through all the changes with my Airport Utility. I even reset my Macbook Air to factory default settings. Still I have the same issue.

What can I do to troubleshoot this problem?

Solution 1:

Have you tried going to the Network preference pane in System Preferences, clicking on Advanced, then Wi-Fi, and deleting all the Preferred Networks? I seem to recall having the same problem a few years ago, and deleting the networks fixed it.

Solution 2:

Deleting all networks in Mac, System Preferences, Network fixed the identical problem for me.

Solution 3:

The following are all suggestions I've tried from different sources:

• moving preferred network to top
• clearing all WiFi passwords (including those from the keychain) and reconnecting only to the preferred network
• disabling bluetooth
• forcefully removing network configuration files
• adding a fixed DNS server

What actually helped was to reset the SMC and reset the PRAM. Now the Mac connects instantly to the WiFi. And it fixed the ping delays as well I had (ping times were up to 4 times higher than from another Macbook).