Safari wants to use the “Local Items” keychain.

As we have gone to user library ~/Library keychains & emptied only the contents of keychain folder & NOT Keychain folder into the trash , because pop - ups were creating & prompting to enter passwords .

Now when you change your login password by going to users & groups > change password , it will match your keychain password & it is always kept the same as per article : Keychain Access: login keychain

And , when ever you login to apple id , I cloud id , webmail they will be filled up in empty keychain .Open safari & its preferences & click on Autofill check the box of user name & password so that when you login the password will be automatically filled up in the keychain & passwords are saved in encrypted form , even you can not read the passwords an article for it : macOS Sierra: keychain , your wireless network password ( is already filled up - you must verify by opening airport utility via spotlight & click on edit enter your wireless network password ) .

You can follow a method to avoid keychain corruption :

Open keychain access via spotlight , choose its preferences ( press command + comma ) , click on general tab & select show keychain status in menu bar a padlock icon appears in the menu bar at the extreme top right hand side of your desktop .

To lock the screen , manually click the padlock icon & choose lock screen as per this article : Improve the security of your Back to My Mac network - Apple Support

Note : The user must " ALWAYS " write down the four digit I cloud verification code , web mail id , I cloud id , Apple ID , wireless network id , login name & their passwords in a diary .

If your iCloud Keychain is corrupted then before following the steps , make sure you must have four digit I cloud verification in your records , all web mail id . I cloud ID , Apple ID , wireless network ID & their passwords respectively & registered mobile ( switched as on ) .

Click on go to go folder & type ~/Library go to folder keychains & select ( can use command + A ) alfa numeric folder , loginkeychain -db , meta data .keychain -db & delete ( command + delete ) to the trash . Restart & empty the trash .

A pop - up appears on the desktop this Mac can’t connect to I cloud because of a problem with ……web mail is written open I cloud preferences to fix this problem

( a ) later ( b ) I cloud preferences , so click on I cloud preferences .

Go to system preferences click on google mail , contacts & 3 more it prompts to enter web mail password , click on next .

Then click on I cloud , I cloud drive & 8 more on the right side check the box of key chain , an pop -up appears enter your Apple ID password & set up I cloud keychain .

Password ….required enter the password in the empty field ( a ) cancel ( b ) ok , click on ok

An pop up appears to set up I cloud keychain on this Mac request approval from one of your other devices using I cloud keychain .if no other devices are available , use I cloud security code ( a ) use code ( b ) cancel ( c ) request approval so , click on use code .

Enter your four digit I cloud security code & click on next enter the verification code ( 6 numbered ) sent to the mobile .

Open airport utility via spotlight & click on base station & enter the wireless network password

( a ) remember this password in my keychain ( cancel , ok) so click on ok .

Open safari & set the home page once again .

Note : The above method will empty all your passwords from the keychain , but if you have 4 digit I cloud verification code that is constant for the user , it is very easy to configure the iCloud Keychain once again .

I have narrowed the issue down to the iCloud keychain locking when It doesn't seem it should, i.e. when I'm logged in and using the mac. On the Mac I have that doesn't give me this problem, when i log in, the iCloud keychain unlocks and stays locked.

On the Mac where I get the message, the iCloud keychain locks after a certain period of time, that's when the pop up message appears.

So it would seem the issue is how to keep the keychain unlocked?

OK, finally worked this out, hope it helps someone else with the same issue. The reason the pop up message occurs is due to the keychain being locked, the password unlocks it. After a period of time, it seems to lock again.

For me the problem seems to be the "Require Password after sleep or screen saver begins". I unchecked this box, rebooted my Mac and I had no problems. I then checked the box again and continued to have no problems and haven't since! I had the exact same problem on a second Mac and following this procedure, also eliminated the problem here.

Somehow it would seem the Mac got confused and thought it was in lock mode and constantly locked the keychain. Not sure what triggered this, but fixed now!!

Keychain Issues - Resolve see post by Kappy

I'd think you should disable then reenable iCloud Keychain.

in keychain access you want to see iCloud not local.

Hey Jake6877 - how did you go with your fix, did it resolver your issue permanently?

Thanks that last link goes through all the same steps and is pre Sierra, so I've done everything they've all said to know success. Would be good to see how Jake6877 went!