Much contents missing inparticular PDF documents

[RainerBielefeld]

Steps how to reproduce with PDF Viewer 2.2.255 and unzipped unofficial (by wg9s) De SeaMonkey 2.53.1 (NT 6.1; Win64; x64; rv:60.0) Gecko/20100101 Firefox/60.0 Build 20191207130010 (Default Classic Theme) on German WIN7 64bit:

Open https://braunschweig.nahverkehrsdaten.com/download/neuesnetz/Fahrplan-2019_Grundlagen_Web.pdf

Expected: shown completely
Actual: most contents missing

[RainerBielefeld]

This is not a new issue for PDF Viewer 2.2.255

[RainerBielefeld]

Probably related to my User Profile, at least the problem is not reproducible with a newly created user profile and newly installed PDF Viewer 2.2.255.

[linux40]

This solves most problems. In short, reason may be the lack of font.