I bought a secondhand Imac this year. It wa being used by a graphic design company that is now out of business. It has been running well so far, but now the storage is “maxed out” and I cannot even download iOS updates. The “system” memory is completely full (I have noticed this is a software issue for some people). But what I have discovered is that there are 2 hard drives. One small one that appears to be running the iOS and another large one that just seems to be used for storage. However, everything is being downloaded/updated to the small drive and it is maxed out and I assume a full hard drive will also affect the speed/performance of the MAC. Why would they lay it out like this?? I’m planning on reinstalling Mohave now. I have it on a bootable USB drive. Can someone give recommendations on how to layout/format/install across 2 hard drives to optimise the performance of this MAC. I’d assume using the bigger drive with more storage would allow for less problems and faster hard drive speed. Am I missing soemthing? Appreciate rhe help!