When I open a file on one users PC the fonts display fine, yet on another some characters are missing, why?
The MicroStation font resource file ( *.rsc ) used to create the text within the design file was not accessible to the one user and hence displaying incorrectly.
Copy the missing *.rsc file to the users PC at the location pointed to by the variable MS_FONTPATH
or
Check user is using the same configuration as others, such as the Project Configuration file where the MS_FONTPATH is defined.
http://communities.bentley.com/products/microstation/w/microstation__wiki/8817.fonts-in-microstation