Well, I just did a clean install of High Sierra 10.13.3, and once again my different login and Keychain Access passwords weren't perpetuated nor was my login keychain populated with the entries in my 10.12.6 login keychain.
Looks like I'll never get to run High Sierra. :shrug: (at this point)
Bug report filed.
More: I just found
High Sierra lost my Mail passwords? which, beginning at #11, hits my problem on the head.
And I just had a flash of insight: Migration Assistant now asks me to choose a password for each admin account BEFORE it migrates my data, and I use the same login password that I've used since time immemorial, NOT my different Keychain Access password, so I'll guess that my data isn't being migrated because MA can't access it, and I'll also guess that if I use the KA password my data will be migrated, and I will
hopefully be able to restore my original login password, i.e. my different passwords situation, afterwards.
If so, this is a bad oversight on Apple's part.
More later.
