I don't own a PC, so none of the pre-2018 links lead to anything I can use.
The machine is not booting and I'd like to try to recover this by using it during OS X install on another MacBook, or at least mount it as an external drive. Select Clone from the drop-down list and select old Mac SSD as source disk at the From column and new SSD drive as the destination disk at the To column 3. I have the same SSD from a 2014 MacBook Air (A1466) and it is marked as a 'Sandisk SD6PQ4M' 256G drive.
When you boot from that installer - the trick will be wiping both the SSD and HDD entirely - then getting it back into Fusion Drive configuration. Connect new SSD to Mac computer and run EaseUS Todo Backup for Mac 2. Then delete about 30 GB of space so you have room to get a clean installer and make a bootable install drive with the OS of your choice. What would be easy is to make a backup of all the files you care about - preferably using Time Machine and a second clone copy if you're not sure Time Machine will work for all your files as a just in case. But on the SSD I would like to have the OS on it. I would going to keep both drives in the computer as I would like to use the HDD for storing music, pictures etc. No - that won't be easy at all but it's exactly what Fusion Drive was engineered to do. Hi, I have a 27 IMac Mid 2011 It currently has the standard HDD in it & Im going to install a new SSD.