Keychain password windows close immediately

No need to uninstall malware bytes , right now its not striking 😢 why the keychain access window quits after a while , and with what method safari passwords were restored , in safari preferences > autofill all boxes are checked .

Please take opinion with apple support senior advisors they can only guide you , reinstalling the OS you are avoiding 😢 .

Take opinions from apple support senior advisors , a step is there is enter into user library macOS Sierra: Library folder

Find a folder preferences > drag and drop com.apple.keychainaccess.plist to the desktop restart the machine open keychain access via spotlight see if it sticks .

But this is only a suggestion don't do it take suggestions from apple support some more complications can be created .

Did you tried to create a new user account How to test an issue in another user account on your Mac - Apple Support just observe the results in it and dont delete the old user account .

And try to reply what are the results .

For some specific reason , you turned off iCloud Keychain syncing for all of the devices .

You mean click on system preferences > iCloud and uncheck the box of keychain or sign out from iCloud account .