Apple Mail cuts off right edge
This is a known issue in Apple Mail. No amount of rebooting or reinstalling will change the outcome.
Work around (see screen grabs below for more detail)
1) When you print, create a new paper size (you only need to do this once). For the US you can create a 9in x 11in letter paper size. This is slightly larger than the 8.5in x 11in standard. But this is where you are fixing Apple's bug.
2) Then from the Print window you click on PDF > Save as PDF
3) Open the saved PDF in Preview or Acrobat and print with "Scale to Fit" or "Fit" selected.
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Screen Grabs
Change the Paper Size
Save as PDF
MacBook Air