Can this migration be cleaned up?
Long story, not sure how to make it short. I have a mid-2010 iMac running High Sierra (iMacs of this vintage cannot run Mojave). I was having a ton of problems with it and finally threw in the towel and bought a brand new 27" iMac running Mojave. When I turned on the new iMac, it wouldn't let me sign on with my existing user name and sign on, told me I had to create a new user name and password. So I did that. Saw instructions to migrate what was on my old iMac to the new using Migration assistant. Couldn't get it them to connect via wifi so decided use WD My Passport back-up drive directly connecting it via USB. Migration finished and I ended up with both user IDs, each with it's own splash page, Mojave for new user ID and High Sierra for old user ID. All data is on the hard drive but I can't access any files - music, photos, documents with the new user ID information, only iCloud items. What do I have to add/delete until I have one user ID using Mojave with access to all of my files? Any advice? Thanks.
iMac 27", macOS 10.14