Chosen Solution
I just finished installing the 32 GB upgrade to a new Mac Mini 2020/2018. Only difficulty was re-installing the antenna cable (not the screw, the cable). Tiny fingers help. But I do have a problem - Ordered the memory from Crucial (as I have for years…decades? For a variety of computers). Installed a single 32GB SO-DIMM in the slot closest to the center of the device and removed the 2 x4 GB SO-DIMMs. But the About Mac is still reporting 2x4 GB in the 2 slots. Rebooted a couple times, no change. Very strange. Anyone got any ideas? BTW: Writing this on the Mac Mini, so it does power up correctly, and connects to the internet correctly.
I would try resetting the systems NVRAM (PRAM) and SMC systems to see if that helps How, When, & Why to reset the PRAM & SMC on your Mac You may need to move the SO-DIMM to the other slot.
