Unknown error signing into iCloud

Let me be more specific. I haven't changed my Apple ID or password in the past few months. Everything works fine on the iMac until it doesn't. No pattern as to why, but I may get email one minute and the next it says I need to sign into my iCloud account. When I enter the correct password it rejects it saying I am using the wrong password. If I restart my computer the problem clears up ... until it happens again. Using System Preferences does not solve the problem. I'm not sure where the glitch in the system is, but there surely seems to be one. (I have not problem connecting with my phone or iPad using the same password.)

You realize that there are no Apple representatives here, right? We're all users like yourself. If you want to report problems to Apple use this link: https://www.apple.com/feedback/macos.html

Download and run Etrecheck. Copy and paste the results into your reply. Etrecheck is a diagnostic tool that was developed by one of the most respected users here in the ASC and recommended by Apple Support to provide a snapshot of the system and help identify the more obvious culprits that can adversely affect a Mac's performance.

What to do after you change your Apple ID or password - Apple Support

I didn't change the password recently, but a MBP computer message told me 'trouble signing into iCloud" so I go and reenter the password. The password is rejected three times, even though same password works with the iPhone. I noticed this a few days and hours/day later I saw a calendar item had at last synched. It fixes itself it seems, but this is making me seriously mixed up on my appointments. Randomly my MacBookPro is disconnected from iCloud, not by my choosing. Currently disconnected. 😟

We deleted everything; sign off my icloud account; delete all my keychains; update my Mac software; it worked fine for a few days and then i had to do it all over again. And some things i couldn’t even recover from Icloud. So frustr

So has anyone heard from Apple support? Is it worth it to go to the nearest Apple Genius Bar? I don't want to have to lug my iMac all the way to an Apple Store 30 miles away if it will just keep happening. I don't even want to use iCloud or Keychain....

Same problem for me and my Mac will not print documents on my printer although it is connected, Wifi and Ethernet, and recognizes it but says the printer has an error. All of this started at the same time after the latest big update.

Same problem, did not reset password but randomly started with this 'unknown error'. I did reset my password to try and resolve, no success. I did re-boot, no success. Not happy if I have to go 1 hour to nearest Apple store to resolve!

I have been having the same problem. I reset my AppleID password and have not had any luck. I am able to go onto iCloud through my web browser, but can't seem to sign in through my iMac settings. Each time I type in my information, all the fields reset and I am stuck in a log-in loop.

I was having the same issue when I updated my Macbook 2014 to Sierra. It also was the same time when I updated my password for iCloud. I had to reset my keychains to clear and start everything from scratch on logins. That seemed to do it.

This doesn't seem to address the problem (repeated multiple time below). An iCloud password that works on multiple other devices fails to work on a Mac and gives this useless "unknown error" message. I suspect most of the folks on this thread know that once they change their password they need re-login to all of the numerous systems that require it.

That answer does not work. For some reason I get "An unknown error occurred" using the correct password. If I use the wrong password, I get a different error.

Someone please let me know what is going on

Apple, I get that you're busy pitching your new thousand dollar telephones, but could you please fix this error, or at least do something to make it less UNKNOWN?

How about replying to this thread, Apple?

Something?

Same issue. For nearly a year, I've been having problems and thinking someone hacked into my home network with an old MBP and iPad. (I know, everyone thinks their system has been hacked, I really think mine is, and I've contacted Apple several times, the local PD, and even the local Sheriff, no one wants to touch it, nor do they really seem to care. I've done all the usual passwords, installs, fresh installs, restarts, literally everything in the book). I started getting the "unknown error" about a week ago. I've tried everything listed on this thread.

I tried viewing system logs, which after Mojave became impossible (I remember the System 7 days when you could get into a log and see the problem in five minutes 99.9% of the time). I was also thrown off Apple communities, not with an unknown error but with a forbidden 403 -- I'm on now because I signed in thru Apple Support. I'm afraid I'll be thrown off if I post this, but we'll see. If you have read this far, please continue --

There have been multiple artifacts I've found on the MBP about something called krit-toe project and koar krit-toe (misspellings intentional, be phonetic). Also a project with a four character acronym that starts with fi and ends with ps and the number two. I'm being cautious because I've found nothing of substance about this anywhere on the net, except some really intense high tech sites which weren't that easy to find or understand.

There is a bunch of other activity on my system, and has been, but I'm going to try to post this and contact apple again next week. Another issue I've had is no matter what I do or how I install, I don't sign into my disk anymore, it goes right to my user account and no one can tell my why I no longer have disk-level filevault.