Short version - email account was hacked. I changed the password and now I can log into the account online. OS/x sierra apple mail would not recognize the password change - insists the password is wrong. So basically I don't use that email much anymore - I try limit it to junk email and look at on my tablet. The account is not active on my iMac That email was the primary email listed on my icloud account. I ended up creating a second (now primary email) and a 3rd email addy for backup. Changed my icloud primary email to the new primary email and listed the third email addy as the icloud backup. Great, no problem. icloud works fine. The original email addy is no longer associated with that icloud account. I can log into the icloud account with no problem. My iMac, however, insists the old primary email is what my computer needs to use. If I open system preferences and go to icloud - it lists the old primary email and wants a password to that icloud account. There isn't one. I've tried all the passwords I've used and none of them work. I can't change the user profile without logging into that icloud account. Same thing with keychain. If I try to turn on keychain - it wants the password to the icloud account that isn't. The imac did an update on Saturday - I'm not all together sure what happened, but the imac would not accept my password to even log me in after that. 3 hours on the phone with apple support and we ended up deleting the user account, and reinstalling from time machine. After that I was able to get in on another admin account and reset the password to my user account and get into the machine. I need to know how to change my User ID to a 'new' icloud account without logging into the 'old' account. I think.