To elaborate on that, my work computer is a Macbook Pro encrypted with FileVault. I was away for a few weeks vacation and coming back I can't log in. My password is correct. I've been using it for a few months and I have no doubt in my mind about this password.
I know last time I reset the corporate password (every 3 months), usually it synchronizes with FileVault. This didn't seem to happen as my corporate password is different than FileVault password. That said I thought maybe it just synchronized. I tried the corporate password which also fails, and I'm also sure is correct since I can log into other systems with the same password.
After a day of trying to log in, and looking for the recovery key, which consequently I could not find :( I've pretty much given up and will be starting from scratch tomorrow, but I really don't understand how the password can just change by itself. I really want to understand how this can happen since I know my password and it should work, but doesn't, and now I'm going to lose days setting everything up again.