probably some formatting getting lost in the migration from the older version
of Excel but just a guess.

If you want the grid lines the easiest way to get them is to go to the top
left corner of your work sheet and click, this selects the whole sheet.  

then on the home tab in the font section select the border drop down
(between the Underline & the bucket) and select the all borders (6 from the
top)

It should then print borders for your entire print range.

not sure if this cures the underlying problem but it should get you where
you need to go.