I have long used the Adobe Reader plug-in to view pdf files within Firefox on my Windows desktop at work. While I can still read those files using the external Adobe reader, the internal option has stopped working: if I request a file (after clicking on "allow"), Firefox entirely hangs for several minutes, and finally displays a blank page. The same occurs for (Shockwave) Flash, for which I do NOT have the external recourse. Both Firefox (46.0.1) and the Adobe Reader plugin (15.16.20039.54196) are up to date. On my laptop (same system, Windows Enterprise 7) and same Firefox and plugin versions, everything still works fine. Is there some other Firefox option which I perhaps need to look at? Apart from that, two differences between the laptop and work machines may be relevant: laptop is 64-bit, work is 32-bit, and centrally-maintained work computer may have tighter security. Any ideas as to what the problem could be? Thanks.