New SSD not detected on MacBook Air 7,1

Solution 1:

1. Start recovery mode with CommandOptionR.

2. Open Terminal, and run below commands:

   diskutil list
   

3. Find which /dev/diskX is yours, usually disk0. Once you identify your disk, erase it with diskutil

   diskutil eraseDisk JHFS+ MacOS /dev/disk0
   

After this, I was able to restore using Time Machine and even install Mojave, giving me an option to chose internal transcend drive for install

After erasing disk using Disk Utility, Time Machine nor Mojave install was working. Mojave was showing my internal Transcend drive greyed out, but this worked.

Solution 2:

I tried this on a 2015 13" MacBook Air and terminal did not show my ssd. looked everywhere nada!

then I tried the old start up in target disk mode!! Plugged it into another air (with a thunderbolt cable), and presto could see it and format from disk util.