I just installed a 240GB SSD in my 2017 MacBook Air, and it will not connect to the internet over my Wifi. I used Command-Option-R on power-up. When I power up, all I get is a spinning globe that quickly has a triangle with an exclamation point and the message 'apple.com/support -3403F'. I cannot connect to the internet to start the OSx download process. How can I get to the point of using Migration Assistant on the MBA and my old MacBook?

Any help would be greatly appreciated!!!
Honestly it sounds like the system never gets far enough to enter internet recovery mode. A sign that there is likely a hardware issue. There are a lot of possibilities but a few spring to mind.


New SSD not seated properly or something got in the connector
Bad new ssd
System damaged when the replacement was done
Incompatible SSD


First I would take the new SSD out, blow the contacts clean with canned air and closely examine the connectors on both ends. Then replace it carefully, making sure everything is seated properly and try again.

I would verify that what you got is what you ordered and that it is indeed compatible with your system. Please include the make/model of SSD in your question. We may be able to help make that determination.

Put the old drive back in and verify it works, if so -sigh of relief- you didn't brick your Mac. If your replacement SSD came with an external USB case you could put it in the case and plug it into the Mac and verify it works. If it doesn't, return it. If it does, call the vendor's tech support. Tell them the symptoms and see what they can do. Possibly replace it, maybe with a different model.