Have you tried repairing the keychain? Sometimes that will help. Otherwise, the last section of the following may be helpful.
Forgot Your Account Password
For Lion, Mountain Lion, or Mavericks
Boot to the Recovery HD:
Restart the computer and after the chime press and hold down the COMMAND and R keys until the menu screen appears. Alternatively, restart the computer and after the chime press and hold down the OPTION key until the boot manager screen appears. Select the Recovery HD and click on the downward pointing arrow button.
When the menubar appears select Terminal from the Utilities menu.
Enter resetpassword at the prompt and press RETURN. Follow
instructions in the dialog window that will appear.
For Snow Leopard and earlier with installer DVD
For Snow Leopard and earlier without installer DVD
Tutorial: Resolving Keychain Issues
If you can't access your keychain, or forget your password If you can't get into your keychain file because you've forgotten your password or the keychain file appears to be corrupt, there are a couple of options.
First, if you've forgotten your password, you can use the "Keychain First Aid" utility to make the keychain password the same as the login password. This can be accomplished via the following process:
1. Open Keychain Access (located in Applications/Utilities)
2. Go to the "Keychain Access" menu and select "Preferences"
3. Click the "First Aid" tab
4. Make sure the "Synchronize login keychain password" box is checked
5. Close the Preferences window
6. Go to the "Keychain Access" menu and select "Keychain First Aid"
7. Enter your username and password
8. Click the "Repair" button
The second option is to completely delete your keychain then recreate it. This routine is useful if your keychain appears to be corrupt or otherwise inaccessible. This can be accomplished as follows:
1. Launch Keychain Access (located in Applications/Utilities)
2. Click "Show Keychains" in the lower-left corner of the window.
3. Select the problematic keychain from the left-hand pane.
4. Navigate to the "File" menu and select "Delete Keychain '(name of keychain)'"
5. Check all options for deletion and press "OK"
6. Create a new keychain by going to the "File" menu, then "New" and selecting
7. You can now make this keychain your default if you desire by selecting it, then
going to the "File" menu and selecting "Make '(name of keychain)' Default"
Login as root and perform repair In some cases, problems with keychains can only be resolved when logged in as the root user.
First, you want to enable the root user:
After enabling the root user, and logging in under this account, again open Keychain Access. First attempt repairs using Keychain First Aid, and failing that, delete then recreate the keychain as described above while logged in as root.
Persistently asked for stored passwords If you are persistently asked for passwords in various applications that you have specified should be remembered in a keychain, your "login" keychain may not be active for one reason or another.
Navigate to ~/Library/Keychains/ (this is the Library folder inside your user's home folder). Find the file named "login.keychain" and double-click it.
Failing that, select the "login" keychain within the Keychain Access application and make sure it is the default keychain by going to the "File" menu and selecting "Make 'Login' Default"
Turn off Keychain synchronization in applications having problems If specific applications are experiencing issues when accessing password-protected material, the Keychain may be to blame.
The above comes from an article published on MacFixit.com.
Verify a disk
I suggest that you use disk utility to verify that your startup disk is OK. You will not be able to repair the file system
Macintosh-HD -> Applications -> Utilities -> Disk Utility
Start up disk utility. On the left pane view, you will see a list of all your disks.
Click on your startup disk.
Click on the First Aid Tab.
Click on verify.
Hopefully your disk will verify. If not, you have to boot from your installation DVD or recovery partitition and run Disk Utility from there to attempt to repair your file-system.
Repair disk permissions
On the disk first aid tab, click on Repair disk permissions. Permissions can get messed up when installing software. Never figured out why. I haven't had a problem, but others have. --------------