Yesterday Adobe released Flash Player 11.3 which included a new Protected Mode for Firefox – this is a new security enhancement designed to limit the impact of attacks launched from malicious SWF (Flash) files against Adobe Flash Player when running in Firefox 4.0+
It applies only to Windows Vista and Windows 7 – so XP and Mac users can ignore this article (any Flash issues you have can’t be related to Protected Mode). Updated 27th July – see updates at bottom of this article.
Protected Mode Issues – Whilst it is a welcome security improvement, early reports are coming in from some Vista and W7 users that it may cause problems with Flash content – it either crashes Firefox 13 or fails to display Flash content correctly. Adobe have released a (hopefully) temporary workaround for this issue which involves disabling Protected Mode.
Only apply this workaround if you have problems with Flash Player since upgrading to version 11.3 (and are using Firefox on Vista/W7).
To Disable Protected Mode – Close Firefox. You now need to edit an Adobe configuration file called mms.cfg which is located in the following folder:
Windows 32bit – C:\windows\system32\macromed\flash OR
Windows 64bit – C:\windows\syswow64\macromed\flash
Tip: to edit this file, when you double click it you may need to choose ‘Select a program from a list of installed programs’ then select ‘Notepad’ then press OK to open the file in the Notepad text editor.
Add the following line then save the file and close it: ProtectedMode = 0 (The value is a zero, not the letter o). If you do not have a mms.cfg file in the relevant folder, create a new blank text file using Notepad, type in the line above and then save it as a file called mms.cfg in the relevant folder.
Hopefully this will cure the Flash Player issues until Adobe (or Mozilla) can release an update to fix the problem. Once they have released an update/fix you should re-enable Protected Mode for best security.
To Enable Protected Mode – Close Firefox and edit the mms.cfg file again – delete the line you added earlier then save the file and close it.
Other Steps – The problem may also be caused by conflicting add-ons. Mozilla have published a couple of solutions here which include disabling the faulty RealPlayer Browser Record add-on.
UPDATED 17th June 2012 – Firefox 13.0.1 has now been released with the following fixes:
- Flash 11.3 sometimes caused a crash on quit
– Windows Messenger did not load in Hotmail, and the Hotmail inbox did not auto-update
– Hebrew text sometimes rendered incorrectly
The Flash fix may help users who experienced Protected Mode crashes when closing Firefox (though it may not fix crashes during playback of Flash content). Get the latest update from Menu bar \ Help \ About Firefox.
UPDATED 27th July 2012 – Adobe have released yet another updated version of Flash Player (11.3.300.268) for all web browsers to (hopefully) resolve these problems – see article here for details.