I suspect that one way or another, your older computer had Arial Unicode MS Bold installed, although it was not installed by either Windows, Office, or any Adobe program. The normal substitution fonts within either Adobe Reader or Adobe Acrobat cannot provide substitutes for most of the characters supported by Arial Unicode. The problem is that Arial Unicode is a font that support a large number of glyphs and encodings. That would confirm that the problem is due to the font not being installed on your system. Next to the font name, it should not say ( embedded). Open the Fonts pane and scroll down looking for Arial Unicode MS, Bold. To confirm that the font is not embedded within the PDF file, open the PDF file and press Ctrl-D. The last Microsoft product to include Arial Unicode MS Regular was Office 2010 which did not include the bold version of this typeface. Most likely the problem is that the PDF file does not have Arial Unicode MS Bold embedded although text within the PDF file is formatted using this font and that unlike some previous versions of Microsoft Office, recent versions of Office that are compatible with Windows 10 include neither Arial Unicode MS Regular nor Arial Unicode MS Bold.
