Originally Posted by
corporate-wage-slave
The maximum LHR layover for United to SAS transfers is 23 hours and 59 minutes on the schedule. Which, incidentally, outside the USA is the norm. It should have been through checked from the start. Assuming this was either one reservation or an agreed on-carriage arrangement.
That's true for faring. However, UA uses its own rules for baggage, and generally will not check luggage through an overnight transfer.