I’ve been trying to install elementary on my mid 2010 17" mbp. I’ve created a few different flash drives using both Etcher and DD. I’ve even verified the ISO hash. No matter what media I use I wind up here after selecting the bootable usb. Google has not been helpful in figuring this out. Anyone else seen this?
Try SMC / PRAM Reset?
With references to APFS and fusion, it seems like it might be trying to mount a visible filesystem.
If the intention is OS install, try erasing the disk from recovery mode and formatting as something ‘boring’ like ExFAT