Kernel Panic AHCI iMac SSD Upgrade

Hey everybody, here we are today with an iMac that was just only supposed to be a hard drive replacement and it kind of threw us a curve ball. I want to share that with you guys because you might run into something similar. The iMac came in with no hard drive present, a folder on startup. Primarily, the customer spoke with apple and they put the device into recovery mode and disk utility didn’t see a hard drive so we installed a hard drive and we thought that was it. So, the computer has a 3tb drive which we replaced and when doing the new install the pc kept crashing and restarting so we thought it was the OS so we installed Catalina and the same thing it kept crashing. I talked to the customer to ask him for more information about the device and he said he was having Kernel Panics and crashes until it got worse and worse which is why he brought it in, he realized that the problem started after an update of Catalina. The next step was to boot it up to an older OS and see how it ran before getting into a disassembly. So, with the external drive, we saw things were good so we said OK we are going to do it and replace his drive. In the install when I went to format the drive, I noticed an SSD drive and I saw it was a 128gb drive which was the fusion drive. We did not notice the drive; at the end of the story, the fusion drive was causing the problem. A fusion drive is a mix of an SSD and a hard drive so the info you are using will be stored on the fusion and then the rest on the hard drive and vice versa. Nowadays we don’t need a fusion, what I tried doing was formatting it to a format that could not be used. After we restarted the computer again the drive never showed up again and that was a clue that something was wrong. The way we took it out was simple, you’ll see videos online that they have a full disassembly, what we were able to do was get the right-side speaker off and we were able to access the head of the screw from there and with a needle nose plier we were able to take it out without a full disassembly. With it out we fixed the issue and it was much easier. With an SSD drive, you do not need the fusion SSD drive anymore so it was causing the computer to crash and give us Kernel Panics with it gone the computer was working better than before. And that’s what’s going on at PC911.