Q: mac seems to open after password and then asks for password again

Hi Tescat,

Sorry to hear that you are unable to login to your Mac. Let's see if we can get you logged back in. 

I would try to reset your password for your account. I would start by restarting your Mac to OS X Recovery and then use terminal to reset the password. Take a look at the User Tip below to walk you through this in more detail. 

Reset the user password in OS X Lion, Mountain Lion, Mavericks and Yosemite
https://discussions.apple.com/docs/DOC-4101

If that doesn't work, you may want to try using your password for your Apple ID. You might have changed the preferences for your password to use this instead of a separate password. 

Another option would be using the Password Recovery Assistant.  This will only be an option for you if you enabled FileVault on your startup disk.

If your startup disk is encrypted with FileVault, you can enter your Recovery Key as your password or you can restart your Mac to use the Password Recovery Assistant. Use these steps to open the assistant:

1. Wait a few moments at the login screen without typing your password. A prompt should appear telling you that you can turn your Mac off and back on again to recover your password.
2. Press and hold the power button for three seconds to turn your Mac off.
3. Press the power button normally to turn your Mac on. 

When the Reset Password window appears, follow the onscreen prompts to get help logging in.

Have a good day