Suddenly Can't Open Certain Sub-Accounts

Whenever I try to access the Guest account or my kid's sub-account I get the infinitely-spinning beach ball (and have to do a hard shutdown). I have no issues and my wife has no issues with her account. I do have parental controls on for the Guest/Kid accounts, but that's nothing new. However, I have recently installed Little Snitch - but then uninstalled it hoping it would eliminate this issue. No dice.

Anyone have any idea what's going on here?