OS X log in cookie? It thinks I am logged in but I am not! I can't log in!

Question

Hello, please help me!
I'll try to be concise.
After plugging in a USB microphone [that i normally use woithout problem] my mac froze up. I waited 5 minutes then held the power button [mac mini] in to force a restart. Afterwards when i try to log in I get the following message;—
you are unable to log in to the user account "username" at this time
after a few tries i sed the master password to change the account password—which worked. I know this because the new password gives the response;--
you are unable to log in to the user account "username" at this time
...whereas the old password or wrong password gets the shaky window. So the password is being changed.
I have a 2nd admin account that i never use. I logged into it and repaired the permissions, but it didn't help.
All my stuff is in the 1st user account!
***I have searched the web and read about how it might be that a type of cookie exists when I am logged in. And that OS X thinks I am still logged in ....thus the error message. There was talk of using terminal and command line stuff —which I've never tried before—to delete/change this cookie, and therefore solve the problem.
By the way, both my accounts are admin acounts and both use filevault.
The photos from my young daughter's birthday are on there, besides a million other things.
If someone knows this situation already and can help me, I will be over the moon and back up daily from now on...I promise!!
Stewart

Answer 1

Thanks for the link, appears somebody was confused by it though & did a no-no...
Hello, I have delete the sparseimage file in /Users/.<username>. and reboot, it still said 'You are unable to log in to the user account "username" at this time'.
Now from my 2nd link, but once you get it open you can copy stuff to this account...
1. Log out of your current (FileVault-protected) account.
2. Log in with an account other than the one whose home directory image you want to verify or repair. You can create a new administrator account in Accounts preferences if there isn't already another one you can use.
3. From the Finder's Go menu, choose Go To Folder.
4. Type "/Users/" and click Go.
5. You'll see folder icons for each user account. Select the one that is FileVault-protected (you won't be able to open the folder yet), then choose Get Info from the Finder's File menu.
6. Expand the "Ownership & Permissions" area at the bottom of the Get Info window by clicking the disclosure triangle. You should see "Owner:" set to the shortname of the protected account.
7. Click the small lock icon that's right of the "Owner" field.
8. Enter your administrator name and password.
9. Change the Owner pop-up menu to your current account's short name. The Access menu (under Owner) should change to "Read & Write"; if not, change that menu manually.
10. Close the Get Info menu.
11. Back in the Users window, you should be able to open the folder named after the FileVault-protected account and see the ".sparseimage" file inside.
12. Select the ".sparseimage" file (you won't be able to open it), then choose Get Info from the Finder's File menu.
13. Expand the "Ownership & Permissions" area at the bottom of the Get Info window by clicking the disclosure triangle. You should see "Owner:" set to the shortname of the protected account.
14. Click the small lock icon that's right of the "Owner" field.
15. Enter your administrator name and password.
16. Change the Owner pop-up menu to your current account's short name. The Access menu (under Owner) should change to "Read & Write"; if not, change that menu manually.
17. Close the Get Info menu.
18. Double-click the ".sparseimage" image file. Enter the account's password when prompted. Note: If you do not know the password and mount the image, you may not be able to verify and repair in Disk Utility.
19. In Disk Utility, the ".sparseimage" disk image file should appear on the left side.
20. Select the disk image in Disk Utility.
21. Click the First Aid tab.
22. Click the Verify or Repair disk button, as desired. Note: If the image has issues than cannot be repaired, you may need to transfer files to a different location as discussed in this article.
23. When finished, quit Disk Utility.
24. Unmount (eject) the mounted disk image volume.
25. Get Info on the .sparseimage disk image file again, and change the owner back to the original account name. Note: If this is not done, your Home may not be available when logging in as the protected account.
26. Get Info in the enclosing folder in /Users again, and change the owner back to the original account name. Verify that this is successful by closing and trying to open the account name folder (you shouldn't be able to).
27. Log out and log back in as the original, FileVault-protected account.