This is a heads-up for anyone who's having trouble with Flash in Firefox on Windows after updating the former to 11.3 (which you should, since it fixes a bunch of new security holes).
I've been having a lot of trouble with this new version myself; videos (e.g. on Youtube) have not been playing acceptably anymore, with regular ten-second delays where the video proper isn't being updated anymore, and there's been a ton of crashes (see image).
Poking through the crash reports quickly revealed a Firefox ticket, as well as an Adobe ticket; I cannot say who's ultimately at fault here, but it's worth observing that disabling the new "protected mode" (sandboxing) that Flash 11.3 introduced fixes all the above issues (so far; claws crossed).
Adobe has an FAQ post on how to do troubleshoot protected mode issues, but they want you to go through a long series of attempts at diagnosis etc. first; understandable from their point of view, but unnecessary if you just want to get rid of it. So for all y'all's benefit, here's the important bits:
- Find your system-wide Flash player config file; on a 32-bit Windows, that's c:\windows\system32\macromed\flash\mms.c
fg, while on a 64-bit version, it's c:\windows\syswow64\macromed\flash\mms.c fg. If the file doesn't exist yet, create it.
- Add a line that says ProtectedMode=0.
That's all! Just remember to reenable it (tentatively) when there's a newer Flash or Firefox version again; maybe these problems'll be fixed then (one can hope!), and protected mode (intended to guard against malicious Flash files) should be useful.