Here's a quick description of why password sync issues can happen and how to avoid them:
Why are there TWO passwords on my Mac?
Our Macs at HPPI are set up with Mobile accounts that authenticate with the Aon network. Our macs also have Filevault activated for security, and that means there are two passwords that need to be synced on the mac.
When your mac restarts (or your battery dies) the mac goes into needing the Filevault password for the mac itself at startup, then once the progress bar kicks in, it authenticates with the password you have set for the mac via Aon password and if they match it will go to desktop, if not, it won't.
If your passwords are out of sync and you don't recall which password will get you in at the very first "Filevault" authentication part (your old password), then the only way past this is to log in with a different account on the Mac, once logged in you log back out which takes you to the primary login window and attempt to login to your account again using your most current Aon password that you can recall. If that doesn't work, you can use the "Other" account, and attempt logging in using your Aon credentials at the prompts (i.e Aon ID and Aon password)
How can I avoid this?
Nomad! Use Nomad to manage and reset your password, and this should keep your passwords happy and synced. If not or you don't have Nomad currently, please contact me using our tech support portal