Mavericks - Additional User Accounts disappeared

Hi all,

I got a rMBP (mid-2012) and recently updated to OS X Mavericks.

Before the upgrade I had setup a couple of accounts for sharing with the rest of the Macs in the house, namely for screen sharing and a dropbox folder (an actual folder inbetween Macs as opposed to the Dropbox web service)

These accounts have now disapperead from Settings --> User Accounts

However the services in the Activity Monitor are still running and the users that initiated them are the users I had setup before the upgrade.

How can I cease the services from running? How can I delete the accounts and set them up again if they do not show up in the User Accounts panel?