OSX is repeatedly asking for login keychain password

Solution 1:

It sounds as an issue either with the Keychain App. Try repairing it. To do so just:

1. Locate the Keychain Access application, under /Applications/Utilities.
2. Choose Keychain Access > Keychain First Aid.
3. Enter your User name and Password.
4. Select Verify and click Start.
5. If any problems were found, select Repair and click Start again.

It could be, too, that you've changed your account password without using the Accounts Preferences pane. If that is the case, for your default keychain to be unlocked automatically when logged in, you'll have to Synchronize your Keychain Access and login passwords. To do so just:

1. Open Keychain Access.
2. From the Edit menu, choose Change Password for Keychain "login."
3. Type the former password of the account that you are currently logged in to, then click OK.
4. If you entered the correct password, a new window appears; enter the original password again in the Current Password field.
5. In the New Password field, type the password that matches your current account password.
6. Re-enter the newer password in the Verify field, then click OK.

This is needed because, as Apple explains it:

If you change your account's password using your Mac OS X Install disc (or if your network-based account password is changed due to a network admin forcing a password change), your default keychain password (which uses the same initial password as your user account) does not change. Because of this, you will be prompted to enter a keychain password each time an application requires authentication that your keychain would normally provide.

Solution 2:

I had the same problem. It has bothered me for several weeks on my new Mac. It should be caused by changing Mac password using 3rd party software. On macOS El Capitan and Sierra, there is no Keychain Access > Keychain First Aid. Changing login keychain's password does not help. To solve this problem, you have to reset your default keychain.

Please note: you'll lose all your passwords stored in it.

1. Open Keychain Access, which is in the Utilities folder of your Applications folder.
2. Choose Preferences from the Keychain Access menu (or Cmd,), then click the Reset My Default Keychain button in the preferences window. After you enter your new password (same to the password of your Mac account), Keychain Access creates an empty login keychain with no password. Click OK to confirm. (If you don't see a Reset My Default keychain button, close the preferences window and select the “login” keychain from the left side of the Keychain Access window. Press the Delete key, then click Delete References.)
3. Choose Log Out from the Apple menu to return to the login screen.
4. Log in to your account. Your account password and login keychain password now match.

Solution 3:

The keychain by default locks after some time of inactivity and when the computer sleeps.

You can disable this behaviour on the keychain settings:

1. Select the keychain
2. Edit / Right click
3. Change Settings for Keychain "login"
4. Uncheck "Lock after 5 minutes of inactivity" and "Lock when sleeping" options

Solution 4:

You have 2 Options:

One is to just open the keychain at log in and leave it open - this is not recommended

2- open keychain find the application(s) in question and give them access

see example

you have to select the Allow all applications to access this item