@Tony Roberts when WAC is installed on W10, the data is stored in %AppData%\Microsoft\ServerManagementExperience. Your best bet is to determine what may have modified the contents or removed that folder.
It's possible that your windows user profile became corrupt and a new one was created. In that case, you'll see multiple folders in %systemdrive%\users. Your old profile would be something like [username] where the new profile is [username].[machine|domain] if you find this is the case, you can recover the old connection list from the old profile folder.