I've been sent an Excel file where the top four rows are frozen. When I save the file to .xps, only the last of the four rows is included. What's the workaround?

The workaround possibly may be as simple as attaching it here and having someone look at it.

Have you tried unfreezing?

Adjusting the print layout settings before saving did the trick: even when you say you're aiming for a file to be used online, the conversion persists in thinking in terms of paper.