How to find iCloud password

[Raven]

I have 4 different Apple/Mac devices that utilize iCloud. How to use iCloud properly is sometimes confusing to me. If I change the iCloud password on one device, do the passwords have to be the same on the others?
When I reboot my old 24" iMac (OS10.10.5), it asks me to enter my iCloud password. I do not know what it is anymore here. I've tried every one of my 6 passwords I've ever used and none work. Then I click on CANCEL two times, the iCloud window closes, and the system goes on. I have no idea what CANCEL does or does not do to iCloud.
How can I find the iCloud password or enter a new one here?

Not sure if this is related... some of my most recent 20,000 photos on Photos only have previews on this iMac, and do not export.  If I want to export that photo, I have to go to iCloud.com and download it from there. Yet, all 20,000 photos are visible and exportable from the other devices.
I hope TS has a solution. Much thanks!

[Xairbusdriver]

Your iCloud password is for iCloud not any device. iCloud is an Apple service. Every device and app that uses iCloud will need that password. It should be identified easily in any good password manager where you have stored that and all other important passwords. You can try to find it in Keychain, good luck, I do not consider that a "good password manager".

The easiest solution is probably reset your iCloud password. It involves three simple steps.

• Type "https://www.icloud.com" into any browser. You will probably be shown your Apple ID and two buttons: "Continue with Password" and "Cancel". I think clicking "Cancel" will take you to a screen offering a "Forgot my ID or password" link. Click on that and you can create another password.
• Get a good password manager and use it faithfully.
• Stop trying to remember passwords, that's what computers are for.

[Raven]

Thanks for the explanation. That does make it clearer.
Yet, if my one iCloud password works on 3 devices, why does it not work on the fourth?
And if I reset it, as you suggested, can I use the 3 device password that already works or a totally new one? I'm just trying to prevent another struggle and waste of time today to get this done right. Often these solutions are simple for you TS gurus and a bit of a challenge for Mac guru wannabies like me! 

[Xairbusdriver]

Are you using a password manager or typing in the password manually?

No device "knows" your password. Only the service that wants a password will actually use it. In this case, only Apple will want/need/use your iCloud password, regardless of what device you use (be it an Apple device or something built by any other manufacturer, ie; Samsung, AT&T, Goggle, etc.).

I suspect that the "fourth device" is getting the password by your manually entering it. I further suspect that you are not using a password manager (which don't make typing ererz  ).

[Raven]

I have not used a password manager. Always type in my passwords.

[Paddy]

If you reset your iCloud PW, Raven, you'll have to re-enter it on all devices.

A password manager is recommended, though KeyChain will work in a pinch. Any password that you can easily type in (and remember) is almost certainly not terribly secure, unless it's long - and unless you use a DIFFERENT one for every instance where a PW is required. And by different, I don't mean changing a number on the end. 

And no, writing all those passwords down on slips of paper hidden in a desk drawer or in a notebook is no solution either.

Interesting info on passwords: https://www.grc.com/haystack.htm

[Raven]

Paddy, I do use a different 11-13 digit password for each time I need one (dozens!). I have a unique way of remembering them. I will look up how to use a password manager.

However, that still does not solve my original question. I did change my iCloud password as Xairbusdriver suggested, but...

1. When I reboot my old iMac, the iCloud window shows up and asks for the password. It does NOT accept the password that works on the other devices. I then click CANCEL twice and that window goes away. Problem solved? I don't think so.

2. Another problem, related to this or not, is that not all my 17,500 photos on iCloud are present in Photos on my iMac. No photos are visible here after Dec 2019.
At the bottom of Photos window, it states "17,500 photos. Uploading 13,900 items". That uploading number hasn't changed for weeks.  No idea if it's uploading or stalled. Are those the missing photos?

Any suggestions here? Thanks again, TS!

Aside, I do want to transfer all files to my new 27" iMac, but I want all glitches I have had for a while in Photos, Fonts, iCloud cleaned up before I do that. Trying to fix one glitch at a time now. 

[Xairbusdriver]

I have no idea why the "iCloud" window should appear on boot up. Could you please post a screen shot of the window at that point?

It would also be helpful to see your "Users & Groups" System Prefs. Be sure to blur/hide personal info.

I plan on moving your second question to a new Thread. As you say, "one glitch at a [thread]".

[Raven]

Attached is the iCloud window that shows up each time I restart. I have tried every password I think I have ever used which gets me nowhere. 
Then I click CANCEL. That window comes back. I click CANCEL again. And that window does not come back. I have no idea what has been affected or not...
Other than the missing images in Apple Photos which all show in iCloud.com.

[Xairbusdriver]

OK, according to your Users & Groups window, that “iCloud” window is not a Boot up screen. You have automatic log in set, so you don’t really have any System Log in or “boot up” dialog.
My opinion:

Either that iCloud password screen is open when you Shut Down and you have reopen all open windows enabled

OR

You have not entered your iCloud password in System Prefs on that device.

I am open to other possibilities, however. I’m not yet purfect!

One of the usual secondary advantages of a password manger is that it will automatically enter a password into the appropriate field. You, therefore, completely bypass the human propensity to maek typeing erers. The closest you can get with your method is to copy and paste into a single document the password you are entering into those four devices. Unfortunately, that will be close to impossible with four different devices without being able to screen share with all of them simultaneously. In that amount of time but with less effort, you could start using a good password manager. Alas, that is up to you...

[Raven]

That iCloud window is never to be seen anywhere until I reboot.
As it won't accept my normal iCloud password, and I click CANCEL, I do wonder what I am missing?...other than not being able to access all my photos from iCloud.com

When I go into System Prefs/iCloud and that iCloud window shows up, I cannot find any place to enter an iCloud password. Where is the place to enter it that you have mentioned?
"You have not entered your iCloud password in System Prefs on that device."

I don't understand how to use a Password Manager yet, and will try to deal with that later. Or even which one to choose? 

[Xairbusdriver]

I don't understand how to use a Password Manager

It's not something you have to learn, like Excel or a database or even Word. They are rather simple to use apps that let you record the location/site/company where you need a password, username, PIN, etc. It will generate a unique password of whatever length you want with whatever characters that site allows. You can use it to keep two passwords to two hundred thousand! But you'll only need to remember the one that will open that password manager. A good one will have an app that will run in all your devices and automatically sync all your passwords (and any other data you keep with it) to all devices.

A good one will be available at all times, whether you need a password/info at a website or an order form or an app or anywhere else.

There is nothing to "learn". You simply fill in as many of the fields/text boxes as you want.

As for where to enter your iCloud data, I can only show you the System Prefs in Catalina, I don't have anything running an older OS. In Catalina, iCloud has a couple of prefs right in the "title bar" of the prefs window (see image below). Note that in Catalina, it is called "Apple ID", but that is just one of the two parts of iCloud identity. "Apple ID" is just another term for "username". The other part is your (Apple) password.

In earlier versions of the Mac OS, it was simply called an "iCloud" pref. I think the System Prefs looked mostly the same in High Sierra and Mojave (third image below).

BTW, if you feel some prefs are missing, try looking in the View menu of System Prefs. You can select which prefs show in the window. Avoid cluttering up the window with prefs you may never use?

[Paddy]

Have you gone through all the steps here, Raven?

https://appletoolbox.com/icloud-keeps-asking-for-password-ios-and-os-x-fix/

(obviously, concentrate on the parts applicable to the Mac, rather than the iDevices.)