My account information keeps disappearing from the Launcher

Very often (but not every time), my account information is lost to the Launcher; rather than bringing up the main screen, I am presented with a screen to select a user.

My computer has three users:

• KDLadage --> me
• MCLadage --> my son
• BoundHeart – my neice

Each time this issue presents itself, I am given a list to choose from that includes MCLadage and BoundHeart, but my account (KDLadage) is missing.

I select the 'plus' sign and add my account back in... and I am able to log in and play the game. However, at some point in the near future, my account will (again) disappear, leaving my son's and niece's account available, but forcing me to re-add my account to the game.